Troubleshooting Your Jeep YJ Turn / Hazard / Brake Light Systems

Walt Jaquith

YJ Enthusiast
Supporting Member
Joined
Apr 12, 2020
Messages
111
Location
Lafayette, OR
If you own a Jeep YJ, at the time of this writing it is at least 24 years old. That’s a long time for a rig that was designed in the early 80s, when the American automotive industry was, frankly, not doing its best work. If you’re going to keep your YJ working reliably, you’re going to need to give it some love. The lighting systems are common failure points on this rig. In this article, we’ll look at how to get the turn/hazard/brake systems working and keep them that way.


System Overview
The systems we’re looking at are powered from three fuses in the Power Distribution Center under the hood:
  • Fuse 3: 50 Amp, Fuse Block
  • Fuse 4: 40 Amp, Ignition System
  • Fuse 5: 20 Amp, Hazard Flash
Aside from the Power Distribution Center, the major components in the systems are:
  • The Fuse Block (Figure 1), located under the dashboard on the left side of the rig.
  • The Ignition Switch, located on top of the steering column
  • The Stop Lamp Switch, mounted on the brake pedal arm
  • The Turn Signal and Hazard Flashers, located at the top of the fuse block
  • The Turn Signal and Hazard Flasher Switch, mounted in the steering column
  • The lights themselves, mounted at the front and rear of the rig, and also in the instrument panel
Aside from these, there are several connectors, with the main one being C218, the connector for the Turn Signal and Hazard Flasher Switch, located on the right side of the steering column.


Supply Power Checks
There are three checks to ensure that the systems are properly powered:

First, remove both flashers from their sockets in the fuse block. The left flasher is for the hazard circuit, and the right flasher is for the turn signals (see Figure 1). Each socket has two connectors arranged in a “V” pattern.
  • For the hazard (left) flasher socket, the left connector should be energized all the time
  • For the turn signal (right) flasher socket, the left connector should be energized when the ignition switch is turned on.
The Pink/Dark Blue wire connected to the Stop Lamp Switch should be energized all the time. While you’re there, confirm that the Stop Lamp Switch is working correctly by depressing the brake pedal and checking that the White/Tan wire(s) become energized.

Visually inspect the flashers before you put them back in. If either the turn or hazard systems are not working, you can swap flashers and see if that changes which system is failing. If there’s any reason to suspect the flashers, it doesn’t hurt to replace them.

Note: Fuse 3 is labeled “Haz Stop”, but does not protect or control the hazard circuit.

Screen Shot 2020-04-14 at 12.39.18 PM.jpg


Figure 1: The Fuse Block


Supply Power Fixes
If your rig fails one of the power supply checks, the fix is to trace the circuit back to the power source (the battery), and find the component that’s causing the fault. We can reference FIGURE 2 to see what components need checking:

Screen Shot 2020-04-14 at 12.37.03 PM.jpg


Figure 2: The Turn, Hazard and Brake Light Power Circuits
  • The hazard circuit feeds through Connector C114, directly from Fuse 5 (20 Amp) in the Power Distribution Panel.
  • The turn signal circuit feeds through Fuse 4 (15 Amp) in the Fuse Block, the Ignition Switch, Connector 114, and finally through Fuse 4 (40 Amp) in the Power Distribution Panel
  • The brake light circuit feeds from Fuse 3 (15 Amp) in the Fuse Block, through Connector 114 and then Fuse 3 (50 Amp) in the Power Distribution Panel
Pull the fuses and inspect them. It’s usually pretty obvious when a fuse is blown, but I have seen fuses that looked ok but were defective. Don’t overlook the connectors, both in-line and at various components; they are potential failure points. Sometimes simply unplugging a connector and plugging it back in can clean the contacts enough to get things working again. The connector at the turn signal switch is particularly vulnerable to issues due to wear, heat and over-current problems (Figure 3). Look it over for loose or broken wires or anything that looks burned or out of place.

Screen Shot 2020-04-14 at 12.36.15 PM.jpg


Figure 3: The Turn Signal Switch Connector


It’s Probably A Bad Ground
There’s good reason why you hear that phrase a lot when you’re dealing with electrical issues, and especially when it concerns old lighting systems. Using the vehicle chassis as the ground system saves a huge amount of cost and complication, but it does introduce this one issue: There are going to be potential trouble points all over the rig, and any one of them can cause a system failure. Let’s look at some common culprits…
  • Sheet metal screw ground points. These can corrode, work loose, or the crimp connectors can fail. Keep them clean and tight.
  • Component mount points. Some parts such as the YJ tail light housings bolt to the body, and that bolted connection is also a ground path. Tight and clean are the key words here as well.
  • Bulb sockets (Figure 4). This is a very common failure point on older vehicles, and it can cause weird problems where various circuits start to interact (i.e. you put on your left blinker and your tail lights dim). What’s happening is a circuit has lost its regular path to ground, and is grounding through another circuit. Often, the connection point is a shared bulb socket that gets corroded, so the problem shows up a lot with the turn/stop and tail light circuits.
If you are dealing with lighting issues, one of the first and most important things you can do is pull the light bulbs, inspect and clean the bulbs and sockets, replace anything that looks like it needs it, and put everything back together with dielectric grease.

Note: Bulbs that are corroded into their sockets like to shatter rather than come out when you try to pull them. Wear gloves!


Screen Shot 2020-04-14 at 12.31.32 PM.jpg


Figure 4: The bulbs and bulb sockets in a yj weren't awesome when they were new. Age and moisture only make them worse..


Is it the Switch?
If things still aren’t working once everything is cleaned up, it’s time to figure out if the problem is the turn signal switch. By looking at FIGURE 5, we can trace the path of the current through the switch under the different circumstances.

Screen Shot 2020-04-14 at 12.32.55 PM.jpg


Figure 5: The Turn Signal Switch


Brake Lights
When the turn and hazard switches are both “off”, brake light current passes directly through the turn signal switch. The input is the White/Tan wire that we checked earlier. It should be energized when the brake pedal is depressed. The output wires are:
  • Left Turn (rear): Dark Green/Red
  • Right Turn (rear): Brown/Red
Both of those wires should be energized when the brake pedal is depressed.


Hazard Lights
The input wire for the hazard circuit is Pink. It is fed directly from the Power Distribution Center under the hood, through the hazard flasher. When the hazard switch is on, the following wires should have current in an intermittent, flashing pattern:
  • Left Turn (rear): Dark Green/Red
  • Right Turn (rear): Brown/Red
  • Left Turn (front): Light Green
  • Right Turn (Front): Tan
Note that the two front circuits also branch off to feed the turn indicators on the dash.


Turn Signals
The left and right turn signal switches defeat the stop light circuit for that side, allowing the other side to continue to act as a regular stop light while the active side is indicating a turn. The wires for the front and rear turn circuits are the same as for the hazard circuit. The front and rear circuits are on separate contacts in the switch, so it’s possible for one end of the rig to be working, while the other is not.

Below is the information for the various circuits, and a “truth chart” for the various functions. It’s good to check the turn signal switch thoroughly before deciding to replace it, but frankly, if you’ve gotten this far in the testing, it’s probably a bad switch.

Connector Terminal #Wire ColorDescriptionStop OnHazard OnLeft TurnRight Turn
1White / TanStop V+ (From Brake Switch)
2Brown / RedRight Rear Turn / StopV+V+ FlashV+ Flash
3Dark Green / RedLeft Rear Turn / StopV+V+ FlashV+ Flash
4Red / WhiteTurn Signal V+ (Ignition Switched/ From Flasher)
5PinkHazard V+ (From Flasher)
6TanRight Front Turn & Dash IndicatorV+ FlashV+ Flash
7Light GreenLeft Front Turn & Dash IndicatorV+ FlashV+ Flash


Other Things to Check
The likely causes are checked now. The rest are long shots.

The wiring harness for the rear lights runs along the left side of the rig, under the driver’s door and up along the left bed sill. From there it dives into the left rear fender area to feed the left rear lights, and then runs to the right side between the bed and fuel tank. There are one or two connectors under the dash just in front of the driver’s door that feed that harness.

The front lighting harness also runs along the left side of the rig, coming through the main connector behind the fuse block at the firewall. If you’ve gotten this far, that connector is worth checking. Have some dielectric grease handy for putting it back together.

Wires can get pinched between metal components, cut on sharp edges, or cracked and brittle from heat or age. Sometimes a short in one circuit can cause wires in a harness to fuse together and short out. At this point the problem should be narrowed down to a specific circuit (rear left, etc). You may need to unwrap the harness and visually inspect the wires.

That’s all I’ve got. Good luck!

-Walt
 
Last edited:

Blmoparjeep1

New Member
Joined
Aug 17, 2020
Messages
5
Location
Ny
If you own a Jeep YJ, at the time of this writing it is at least 24 years old. That’s a long time for a rig that was designed in the early 80s, when the American automotive industry was, frankly, not doing its best work. If you’re going to keep your YJ working reliably, you’re going to need to give it some love. The lighting systems are common failure points on this rig. In this article, we’ll look at how to get the turn/hazard/brake systems working and keep them that way.


System Overview
The systems we’re looking at are powered from three fuses in the Power Distribution Center under the hood:
  • Fuse 3: 50 Amp, Fuse Block
  • Fuse 4: 40 Amp, Ignition System
  • Fuse 5: 20 Amp, Hazard Flash
Aside from the Power Distribution Center, the major components in the systems are:
  • The Fuse Block (Figure 1), located under the dashboard on the left side of the rig.
  • The Ignition Switch, located on top of the steering column
  • The Stop Lamp Switch, mounted on the brake pedal arm
  • The Turn Signal and Hazard Flashers, located at the top of the fuse block
  • The Turn Signal and Hazard Flasher Switch, mounted in the steering column
  • The lights themselves, mounted at the front and rear of the rig, and also in the instrument panel
Aside from these, there are several connectors, with the main one being C218, the connector for the Turn Signal and Hazard Flasher Switch, located on the right side of the steering column.


Supply Power Checks
There are three checks to ensure that the systems are properly powered:

First, remove both flashers from their sockets in the fuse block. The left flasher is for the hazard circuit, and the right flasher is for the turn signals (see Figure 1). Each socket has two connectors arranged in a “V” pattern.
  • For the hazard (left) flasher socket, the left connector should be energized all the time
  • For the turn signal (right) flasher socket, the left connector should be energized when the ignition switch is turned on.
The Pink/Dark Blue wire connected to the Stop Lamp Switch should be energized all the time. While you’re there, confirm that the Stop Lamp Switch is working correctly by depressing the brake pedal and checking that the White/Tan wire(s) become energized.

Visually inspect the flashers before you put them back in. If either the turn or hazard systems are not working, you can swap flashers and see if that changes which system is failing. If there’s any reason to suspect the flashers, it doesn’t hurt to replace them.

Note: Fuse 3 is labeled “Haz Stop”, but does not protect or control the hazard circuit.

View attachment 115633

Figure 1: The Fuse Block


Supply Power Fixes
If your rig fails one of the power supply checks, the fix is to trace the circuit back to the power source (the battery), and find the component that’s causing the fault. We can reference FIGURE 2 to see what components need checking:

View attachment 115632

Figure 2: The Turn, Hazard and Brake Light Power Circuits
  • The hazard circuit feeds through Connector C114, directly from Fuse 5 (20 Amp) in the Power Distribution Panel.
  • The turn signal circuit feeds through Fuse 4 (15 Amp) in the Fuse Block, the Ignition Switch, Connector 114, and finally through Fuse 4 (40 Amp) in the Power Distribution Panel
  • The brake light circuit feeds from Fuse 3 (15 Amp) in the Fuse Block, through Connector 114 and then Fuse 3 (50 Amp) in the Power Distribution Panel
Pull the fuses and inspect them. It’s usually pretty obvious when a fuse is blown, but I have seen fuses that looked ok but were defective. Don’t overlook the connectors, both in-line and at various components; they are potential failure points. Sometimes simply unplugging a connector and plugging it back in can clean the contacts enough to get things working again. The connector at the turn signal switch is particularly vulnerable to issues due to wear, heat and over-current problems (Figure 3). Look it over for loose or broken wires or anything that looks burned or out of place.

View attachment 115631

Figure 3: The Turn Signal Switch Connector


It’s Probably A Bad Ground
There’s good reason why you hear that phrase a lot when you’re dealing with electrical issues, and especially when it concerns old lighting systems. Using the vehicle chassis as the ground system saves a huge amount of cost and complication, but it does introduce this one issue: There are going to be potential trouble points all over the rig, and any one of them can cause a system failure. Let’s look at some common culprits…
  • Sheet metal screw ground points. These can corrode, work loose, or the crimp connectors can fail. Keep them clean and tight.
  • Component mount points. Some parts such as the YJ tail light housings bolt to the body, and that bolted connection is also a ground path. Tight and clean are the key words here as well.
  • Bulb sockets (Figure 4). This is a very common failure point on older vehicles, and it can cause weird problems where various circuits start to interact (i.e. you put on your left blinker and your tail lights dim). What’s happening is a circuit has lost its regular path to ground, and is grounding through another circuit. Often, the connection point is a shared bulb socket that gets corroded, so the problem shows up a lot with the turn/stop and tail light circuits.
If you are dealing with lighting issues, one of the first and most important things you can do is pull the light bulbs, inspect and clean the bulbs and sockets, replace anything that looks like it needs it, and put everything back together with dielectric grease.

Note: Bulbs that are corroded into their sockets like to shatter rather than come out when you try to pull them. Wear gloves!


View attachment 115629

Figure 4: The bulbs and bulb sockets in a yj weren't awesome when they were new. Age and moisture only make them worse..


Is it the Switch?
If things still aren’t working once everything is cleaned up, it’s time to figure out if the problem is the turn signal switch. By looking at FIGURE 5, we can trace the path of the current through the switch under the different circumstances.

View attachment 115630

Figure 5: The Turn Signal Switch


Brake Lights
When the turn and hazard switches are both “off”, brake light current passes directly through the turn signal switch. The input is the White/Tan wire that we checked earlier. It should be energized when the brake pedal is depressed. The output wires are:
  • Left Turn (rear): Dark Green/Red
  • Right Turn (rear): Brown/Red
Both of those wires should be energized when the brake pedal is depressed.


Hazard Lights
The input wire for the hazard circuit is Pink. It is fed directly from the Power Distribution Center under the hood, through the hazard flasher. When the hazard switch is on, the following wires should have current in an intermittent, flashing pattern:
  • Left Turn (rear): Dark Green/Red
  • Right Turn (rear): Brown/Red
  • Left Turn (front): Light Green
  • Right Turn (Front): Tan
Note that the two front circuits also branch off to feed the turn indicators on the dash.


Turn Signals
The left and right turn signal switches defeat the stop light circuit for that side, allowing the other side to continue to act as a regular stop light while the active side is indicating a turn. The wires for the front and rear turn circuits are the same as for the hazard circuit. The front and rear circuits are on separate contacts in the switch, so it’s possible for one end of the rig to be working, while the other is not.

Below is the information for the various circuits, and a “truth chart” for the various functions. It’s good to check the turn signal switch thoroughly before deciding to replace it, but frankly, if you’ve gotten this far in the testing, it’s probably a bad switch.

Connector Terminal #Wire ColorDescriptionStop OnHazard OnLeft TurnRight Turn
1White / TanStop V+ (From Brake Switch)
2Brown / RedRight Rear Turn / StopV+V+ FlashV+ Flash
3Dark Green / RedLeft Rear Turn / StopV+V+ FlashV+ Flash
4Red / WhiteTurn Signal V+ (Ignition Switched/ From Flasher)
5PinkHazard V+ (From Flasher)
6TanRight Front Turn & Dash IndicatorV+ FlashV+ Flash
7Light GreenLeft Front Turn & Dash IndicatorV+ FlashV+ Flash


Other Things to Check
The likely causes are checked now. The rest are long shots.

The wiring harness for the rear lights runs along the left side of the rig, under the driver’s door and up along the left bed sill. From there it dives into the left rear fender area to feed the left rear lights, and then runs to the right side between the bed and fuel tank. There are one or two connectors under the dash just in front of the driver’s door that feed that harness.

The front lighting harness also runs along the left side of the rig, coming through the main connector behind the fuse block at the firewall. If you’ve gotten this far, that connector is worth checking. Have some dielectric grease handy for putting it back together.

Wires can get pinched between metal components, cut on sharp edges, or cracked and brittle from heat or age. Sometimes a short in one circuit can cause wires in a harness to fuse together and short out. At this point the problem should be narrowed down to a specific circuit (rear left, etc). You may need to unwrap the harness and visually inspect the wires.

That’s all I’ve got. Good luck!

-Walt
Thank you for ALL that info I have my work cut out for me appreciate it
 
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mcpolo

New Member
Joined
Dec 31, 2020
Messages
2
Location
Glendale, AZ
If you own a Jeep YJ, at the time of this writing it is at least 24 years old. That’s a long time for a rig that was designed in the early 80s, when the American automotive industry was, frankly, not doing its best work. If you’re going to keep your YJ working reliably, you’re going to need to give it some love. The lighting systems are common failure points on this rig. In this article, we’ll look at how to get the turn/hazard/brake systems working and keep them that way.


System Overview
The systems we’re looking at are powered from three fuses in the Power Distribution Center under the hood:
  • Fuse 3: 50 Amp, Fuse Block
  • Fuse 4: 40 Amp, Ignition System
  • Fuse 5: 20 Amp, Hazard Flash
Aside from the Power Distribution Center, the major components in the systems are:
  • The Fuse Block (Figure 1), located under the dashboard on the left side of the rig.
  • The Ignition Switch, located on top of the steering column
  • The Stop Lamp Switch, mounted on the brake pedal arm
  • The Turn Signal and Hazard Flashers, located at the top of the fuse block
  • The Turn Signal and Hazard Flasher Switch, mounted in the steering column
  • The lights themselves, mounted at the front and rear of the rig, and also in the instrument panel
Aside from these, there are several connectors, with the main one being C218, the connector for the Turn Signal and Hazard Flasher Switch, located on the right side of the steering column.


Supply Power Checks
There are three checks to ensure that the systems are properly powered:

First, remove both flashers from their sockets in the fuse block. The left flasher is for the hazard circuit, and the right flasher is for the turn signals (see Figure 1). Each socket has two connectors arranged in a “V” pattern.
  • For the hazard (left) flasher socket, the left connector should be energized all the time
  • For the turn signal (right) flasher socket, the left connector should be energized when the ignition switch is turned on.
The Pink/Dark Blue wire connected to the Stop Lamp Switch should be energized all the time. While you’re there, confirm that the Stop Lamp Switch is working correctly by depressing the brake pedal and checking that the White/Tan wire(s) become energized.

Visually inspect the flashers before you put them back in. If either the turn or hazard systems are not working, you can swap flashers and see if that changes which system is failing. If there’s any reason to suspect the flashers, it doesn’t hurt to replace them.

Note: Fuse 3 is labeled “Haz Stop”, but does not protect or control the hazard circuit.

View attachment 115633

Figure 1: The Fuse Block


Supply Power Fixes
If your rig fails one of the power supply checks, the fix is to trace the circuit back to the power source (the battery), and find the component that’s causing the fault. We can reference FIGURE 2 to see what components need checking:

View attachment 115632

Figure 2: The Turn, Hazard and Brake Light Power Circuits
  • The hazard circuit feeds through Connector C114, directly from Fuse 5 (20 Amp) in the Power Distribution Panel.
  • The turn signal circuit feeds through Fuse 4 (15 Amp) in the Fuse Block, the Ignition Switch, Connector 114, and finally through Fuse 4 (40 Amp) in the Power Distribution Panel
  • The brake light circuit feeds from Fuse 3 (15 Amp) in the Fuse Block, through Connector 114 and then Fuse 3 (50 Amp) in the Power Distribution Panel
Pull the fuses and inspect them. It’s usually pretty obvious when a fuse is blown, but I have seen fuses that looked ok but were defective. Don’t overlook the connectors, both in-line and at various components; they are potential failure points. Sometimes simply unplugging a connector and plugging it back in can clean the contacts enough to get things working again. The connector at the turn signal switch is particularly vulnerable to issues due to wear, heat and over-current problems (Figure 3). Look it over for loose or broken wires or anything that looks burned or out of place.

View attachment 115631

Figure 3: The Turn Signal Switch Connector


It’s Probably A Bad Ground
There’s good reason why you hear that phrase a lot when you’re dealing with electrical issues, and especially when it concerns old lighting systems. Using the vehicle chassis as the ground system saves a huge amount of cost and complication, but it does introduce this one issue: There are going to be potential trouble points all over the rig, and any one of them can cause a system failure. Let’s look at some common culprits…
  • Sheet metal screw ground points. These can corrode, work loose, or the crimp connectors can fail. Keep them clean and tight.
  • Component mount points. Some parts such as the YJ tail light housings bolt to the body, and that bolted connection is also a ground path. Tight and clean are the key words here as well.
  • Bulb sockets (Figure 4). This is a very common failure point on older vehicles, and it can cause weird problems where various circuits start to interact (i.e. you put on your left blinker and your tail lights dim). What’s happening is a circuit has lost its regular path to ground, and is grounding through another circuit. Often, the connection point is a shared bulb socket that gets corroded, so the problem shows up a lot with the turn/stop and tail light circuits.
If you are dealing with lighting issues, one of the first and most important things you can do is pull the light bulbs, inspect and clean the bulbs and sockets, replace anything that looks like it needs it, and put everything back together with dielectric grease.

Note: Bulbs that are corroded into their sockets like to shatter rather than come out when you try to pull them. Wear gloves!


View attachment 115629

Figure 4: The bulbs and bulb sockets in a yj weren't awesome when they were new. Age and moisture only make them worse..


Is it the Switch?
If things still aren’t working once everything is cleaned up, it’s time to figure out if the problem is the turn signal switch. By looking at FIGURE 5, we can trace the path of the current through the switch under the different circumstances.

View attachment 115630

Figure 5: The Turn Signal Switch


Brake Lights
When the turn and hazard switches are both “off”, brake light current passes directly through the turn signal switch. The input is the White/Tan wire that we checked earlier. It should be energized when the brake pedal is depressed. The output wires are:
  • Left Turn (rear): Dark Green/Red
  • Right Turn (rear): Brown/Red
Both of those wires should be energized when the brake pedal is depressed.


Hazard Lights
The input wire for the hazard circuit is Pink. It is fed directly from the Power Distribution Center under the hood, through the hazard flasher. When the hazard switch is on, the following wires should have current in an intermittent, flashing pattern:
  • Left Turn (rear): Dark Green/Red
  • Right Turn (rear): Brown/Red
  • Left Turn (front): Light Green
  • Right Turn (Front): Tan
Note that the two front circuits also branch off to feed the turn indicators on the dash.


Turn Signals
The left and right turn signal switches defeat the stop light circuit for that side, allowing the other side to continue to act as a regular stop light while the active side is indicating a turn. The wires for the front and rear turn circuits are the same as for the hazard circuit. The front and rear circuits are on separate contacts in the switch, so it’s possible for one end of the rig to be working, while the other is not.

Below is the information for the various circuits, and a “truth chart” for the various functions. It’s good to check the turn signal switch thoroughly before deciding to replace it, but frankly, if you’ve gotten this far in the testing, it’s probably a bad switch.

Connector Terminal #Wire ColorDescriptionStop OnHazard OnLeft TurnRight Turn
1White / TanStop V+ (From Brake Switch)
2Brown / RedRight Rear Turn / StopV+V+ FlashV+ Flash
3Dark Green / RedLeft Rear Turn / StopV+V+ FlashV+ Flash
4Red / WhiteTurn Signal V+ (Ignition Switched/ From Flasher)
5PinkHazard V+ (From Flasher)
6TanRight Front Turn & Dash IndicatorV+ FlashV+ Flash
7Light GreenLeft Front Turn & Dash IndicatorV+ FlashV+ Flash


Other Things to Check
The likely causes are checked now. The rest are long shots.

The wiring harness for the rear lights runs along the left side of the rig, under the driver’s door and up along the left bed sill. From there it dives into the left rear fender area to feed the left rear lights, and then runs to the right side between the bed and fuel tank. There are one or two connectors under the dash just in front of the driver’s door that feed that harness.

The front lighting harness also runs along the left side of the rig, coming through the main connector behind the fuse block at the firewall. If you’ve gotten this far, that connector is worth checking. Have some dielectric grease handy for putting it back together.

Wires can get pinched between metal components, cut on sharp edges, or cracked and brittle from heat or age. Sometimes a short in one circuit can cause wires in a harness to fuse together and short out. At this point the problem should be narrowed down to a specific circuit (rear left, etc). You may need to unwrap the harness and visually inspect the wires.

That’s all I’ve got. Good luck!

-Walt
Thank You for this, I'm getting ready to tackle this project this upcoming weekend. Question for you, I had to hammer on my steering wheel column last week when my wheel puller snapped a bolt in the steering wheel. Since I did that I lost my turn signals and hazard lights. So I replaced the Turn signal switch this weekend but still don't have signals. Any idea where I should trouble shoot next?
 
OP
Walt Jaquith

Walt Jaquith

YJ Enthusiast
Supporting Member
Joined
Apr 12, 2020
Messages
111
Location
Lafayette, OR
Thank You for this, I'm getting ready to tackle this project this upcoming weekend. Question for you, I had to hammer on my steering wheel column last week when my wheel puller snapped a bolt in the steering wheel. Since I did that I lost my turn signals and hazard lights. So I replaced the Turn signal switch this weekend but still don't have signals. Any idea where I should trouble shoot next?
Whatever the happened with the column, I'd still approach a turn/hazard problem holistically; start my making sure you've got power coming in where it's supposed to. Check your ground connections. Check the connectors to make sure there's nothing wrong there. Test the inputs and outputs at the switch. You might have got a bad replacement switch. It does happen. Good luck!
 

jeepjoe43

YJ Enthusiast
Lifetime Supporting Member
Joined
Dec 4, 2020
Messages
926
Location
Black Canyon City, AZ 85324
I've not had exactly these kinds of problems, but have had other issues.
I went LED with all my lighting and had to provide a separate ground for the tail lights and add the load resistors to the harness to make them work.
If anyone else is going this route, there are electronic flashers out there, but they may not fit in the fuse block. Wasted $50 myself.
My turn signals work, but the hazards won't stay on.
I think that part is one in the same but it's just not very high on my priority list.
Frankly, after changing out the ignition switch, I'm not terribly excited about digging back into the column.
 

Deep Obsession 1

New Member
Joined
Oct 12, 2021
Messages
3
Location
Elberta, Alabama
I installed new LED tail lights on my 94 YJ. Brake lights work when pedal is pressed. Turn signals both sides work when lever is pushed. But the turn signals will not work with the brake pedal pushed. I found a bunch of really bad wiring issues in back so I cut it all out. Someone hacked it up bad. I tested the factory wires and figured out what did what then hooked up the new LED tail lights. First issue I found was when I turned on the turn signals they both flashed. So after a little thinking I realized they need a diode to stop the current flow back through the brake wires since brake and turn share one wire at the lights. I installed 2 diodes and now brake and turn work separately but they don't play well together. So that's where I'm at.
Any ideas?
 
OP
Walt Jaquith

Walt Jaquith

YJ Enthusiast
Supporting Member
Joined
Apr 12, 2020
Messages
111
Location
Lafayette, OR
I installed new LED tail lights on my 94 YJ. Brake lights work when pedal is pressed. Turn signals both sides work when lever is pushed. But the turn signals will not work with the brake pedal pushed. I found a bunch of really bad wiring issues in back so I cut it all out. Someone hacked it up bad. I tested the factory wires and figured out what did what then hooked up the new LED tail lights. First issue I found was when I turned on the turn signals they both flashed. So after a little thinking I realized they need a diode to stop the current flow back through the brake wires since brake and turn share one wire at the lights. I installed 2 diodes and now brake and turn work separately but they don't play well together. So that's where I'm at.
Any ideas?
You don't need diodes. If you look at the diagram of the turn signal switch you'll see that the switch handles disconnecting what's needed to keep current from flowing back through the system. When the left (for instance) turn signal is activated, the brake circuit for that side is disconnected, leaving the right brake light functioning normally while the left light flashes. If I was experiencing what you are--and I was DEAD CERTAIN that I had everything hooked up correctly--my diagnosis would be a bad turn signal switch.

Edit: And even if I was dead certain I'd hooked everything up correctly, I'd unplug the turn signal stitch and power the connector's downstream terminals one by one to see what lights up.
 
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Deep Obsession 1

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That makes sense.
You don't need diodes. If you look at the diagram of the turn signal switch you'll see that the switch handles disconnecting what's needed to keep current from flowing back through the system. When the left (for instance) turn signal is activated, the brake circuit for that side is disconnected, leaving the right brake light functioning normally while the left light flashes. If I was experiencing what you are--and I was DEAD CERTAIN that I had everything hooked up correctly--my diagnosis would be a bad turn signal switch.
That makes sense. I thought I needed them because I found them in the rat nest wiring I found in the Jeep. I used a standard 12 volt dc tester with light and verified the stock wiring. What each one did. Then I wired the tail lights up according to the LED instructions. So I will remove the diodes and start the process over again.
 

machoheadgames

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Yeah, as Walt says, very likely bad turn signal switch. The turn signal switch has a built in buss bar type deal that connects and disconnects the brake lights when turn signals are activated so that the blinker can be blink and not be overrun by the solid brake light. If your brake lights are not properly being cancelled, or lots of other funky brake vs turn signal issues, 9 times out of 10 the circuits are not being handled properly by the turn signal switch. Easy way to diagnose the switch as bad is plug in a new one real quick, operate it by hand and see if the signals and brakes work properly again.
 

Deep Obsession 1

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Yeah, as Walt says, very likely bad turn signal switch. The turn signal switch has a built in buss bar type deal that connects and disconnects the brake lights when turn signals are activated so that the blinker can be blink and not be overrun by the solid brake light. If your brake lights are not properly being cancelled, or lots of other funky brake vs turn signal issues, 9 times out of 10 the circuits are not being handled properly by the turn signal switch. Easy way to diagnose the switch as bad is plug in a new one real quick, operate it by hand and see if the signals and brakes work properly again.
Thanks for the help. That's why I joined a forum. To get info from people who have these Jeeps.
 
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Paul

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Hello.
I'm new to the forum and need a little help.Please..!
My old 89 YJ is up for restoration ,it's been sitting at the back of the house for about 8 years.
I bought it in the US in 93 and exported 21 years ago.It's going to be my son's 18th birthday present.
One of my first jobs is to install some euro tail lights.So what I understand is Stop/and Turn lights are on the same Wire(black and grey on mine, back left) but I need to separate them because the new euro lights have an orange lens.
Some other post's I have read,talk about running a new wire from the stop under the dash but I can't figure out which one to cut.
Any help would be appreciated..!

P.s. For sitting on grass for 8 years,She still looks great...I think..!

IMG_2297.JPG
 

machoheadgames

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Hello.
I'm new to the forum and need a little help.Please..!
My old 89 YJ is up for restoration ,it's been sitting at the back of the house for about 8 years.
I bought it in the US in 93 and exported 21 years ago.It's going to be my son's 18th birthday present.
One of my first jobs is to install some euro tail lights.So what I understand is Stop/and Turn lights are on the same Wire(black and grey on mine, back left) but I need to separate them because the new euro lights have an orange lens.
Some other post's I have read,talk about running a new wire from the stop under the dash but I can't figure out which one to cut.
Any help would be appreciated..!

P.s. For sitting on grass for 8 years,She still looks great...I think..!

View attachment 118847
You would need to find the output wire from the brake switch that runs to the turn signal switch and cut it, and seal off the turn signal switch end. Then the leftover cut end from the brake switch would need to be extended out to both tail lamps as a brake wire.

The old stop/turn wires will become turn only and go to the amber portion, the new extended wire will go to the brake portion and the old tail lamp wire will go to the dimmer parking/running lamp side of the brake bulb.

Keep in mind the euro lights have no license plate light so you might want to get an aftermarket light. they also do not emit very bright light with incandescent bulbs, so now would be the time to go LED in them if you want them. I tried them on my Jeep but couldn’t commit, I went with super bright quadratec LEDs instead. I wish they made a version with an amber turn strip but oh well.

Sharp looking Jeep.
 
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Paul

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Hi machoheadgames, Thanks for the quick reply.
I have 2 wires coming from the Brake pedal switch,1 black/pink and 1Blue/black is that correct.
They disappear into the wiring loom and I can't figure out where they go after that.

IMG_2299.JPG
 

machoheadgames

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Hi machoheadgames, Thanks for the quick reply.
I have 2 wires coming from the Brake pedal switch,1 black/pink and 1Blue/black is that correct.
They disappear into the wiring loom and I can't figure out where they go after that.

View attachment 118848
I don’t know about the colors but two wires sounds right. One to the battery and one to the lights, and pushing the brake pedal lets the switch connect the two which lights the lights. The output wire goes to the turn signal switch next so look at your turn signal switch connector and see if either a blue/black or a pink/black is there.
 

machoheadgames

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Thanks again,
I will give it another look later today.
I just checked the 1990 service manual. Should be same as 1989 because the colors are the same. Pink is battery and blue goes to the steering column. So you need to cut the blue wire. I could cut it closer to the turn signal switch, but not too close in case you ever wanted to go back. Just put some heat shrink on the cut wire. Then extend the blue wire from the brake light switch to your new euro brake lights.
 

Paul

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OK..I took a quick look,I have Blue/Black going to a connecter on the steering column.
Is that the one ..!

IMG_2301.JPG