Fender turn signals

reidboy1

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Surrey BC
Hey all. I just figured out today that my front fender turn signals only work when the headlights are off, but not while they‘re on. Is this right? If so, can anyone explain why? If they should work all the time, what do I need to do to fix? Thanks.
 
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Yes, they should flash regardless of the headlights being on or off when you use your blinkers. Why? have no idea but bad grounds are always a good place to start.
 
Yes, they should flash regardless of the headlights being on or off when you use your blinkers. Why? have no idea but bad grounds are always a good place to start.
That's what I figured. Tested it again today, and it’s still the same. I’ll have to figure it out
 
Do you have LEDs in either the side markers or the front parking lamps?
Yes, just on the side markers. Everything else is regular. I switched to LEDs here because the left side was out and Cdn Tire didnt have the regular bulbs. But now I’m thinking that maybe the bulb wasnt burned out, maybe it was the connectivity. i could reinstall the regular bulbs, are you thinking the LEDs could be the issue? Don’t see how, but I’m just learning as I go🙂
 
Yes, just on the side markers. Everything else is regular. I switched to LEDs here because the left side was out and Cdn Tire didnt have the regular bulbs. But now I’m thinking that maybe the bulb wasnt burned out, maybe it was the connectivity. i could reinstall the regular bulbs, are you thinking the LEDs could be the issue? Don’t see how, but I’m just learning as I go🙂
The LEDs are the issue, due to the way their circuitry works (or doesn’t work in this case). LEDs only let power flow through them in one direction in most cases. Some LEDs on the market are built in a way that power and ground can be hooked up to either side, but not most bulbs. The ones you got weren’t made that way.

The side marker harness feeds the bulb power from both sides depending on headlights on or off. So you either need a non polar LED or you need to stick to stock incandescents.

If you ever put LEDs in the front grille locations, it’s an even bigger ordeal where you have to rewire the side markers.
 
You were bang on, it was the LEDs! I replaced them with the regular halogen 194 bulbs and the side markers are now operating exactly as they should. Who knew? Not me! Based on the level of detail you provided, I was pretty confident this was going to be the outcome. Now I do know, so thank you very much for your advice. This I why this is such a great site, especially for newbie’s.

I met another YJ Jeeper earlier today picking up a seat part. Told him about the problem and he agreed with your explanation and shared a way to fix it so that you can run either LEDs or halogens in all lights...details below. You likely know this, but passing it along anyways. For what it’s worth, I’m planning on staying with the halogens as it’s OEM or nothing at this stage😀

“These are CEC Industries flashers that have a ground wire. Some of the others that don’t have the ground wire cause issues. I wired both of the ground wires together and then bolted the end of the ground to a bolt under the dash frame. The flashers are installed in the fuse panel under the left side of the steering column. The part numbers are: EF32RLN or EF32RLNP”
 
You were bang on, it was the LEDs! I replaced them with the regular halogen 194 bulbs and the side markers are now operating exactly as they should. Who knew? Not me! Based on the level of detail you provided, I was pretty confident this was going to be the outcome. Now I do know, so thank you very much for your advice. This I why this is such a great site, especially for newbie’s.

I met another YJ Jeeper earlier today picking up a seat part. Told him about the problem and he agreed with your explanation and shared a way to fix it so that you can run either LEDs or halogens in all lights...details below. You likely know this, but passing it along anyways. For what it’s worth, I’m planning on staying with the halogens as it’s OEM or nothing at this stage😀

“These are CEC Industries flashers that have a ground wire. Some of the others that don’t have the ground wire cause issues. I wired both of the ground wires together and then bolted the end of the ground to a bolt under the dash frame. The flashers are installed in the fuse panel under the left side of the steering column. The part numbers are: EF32RLN or EF32RLNP”
Good to hear swapping back fixed your issue. I was pretty certain it would.

As for the flasher, unfortunately that will only solve one problem. LEDs cause several problems. WARNING: none of what I'm about to ramble about matters since you're staying stock anyways, but I may as well explain the deal and how it works for anyone interested.

LEDs draw very little power compared to an incandescent equivalent bulb. The flasher relay is built to blink when a certain amount of power is pulled through it, which is calibrated to how many incandescent bulbs are on the vehicle. On the YJ, the turn signal flasher (not the hazard, there are two total flashers) is calibrated for basically 2.5 bulbs since the front and rear bulbs pull about 27W each and the side marker fender bulbs pull about 12W. When you change to LEDs, you screw up the load, and the flasher stops working. On modern cars, it's computer controller and the computer will blink the flasher in hyperflash mode. So, the flasher you linked is for blinking the circuit properly when you have converted to all LEDs and no longer have the proper load for the stock flasher. The flasher you linked is computer controlled in and of itself, so it knows exactly when it wants to blink.

There are other issues with LEDs, though:

1) they are polar, like you experienced.

Most LEDs will only accept power in one direction, which means ground works on one pin and power on the other, and if the bulb is installed backwards in the socket, it won't work. In your case, the bulb worked half the time, but not the other. Flipping the bulb would have reversed your results. The problem for a polarized bulb in the YJ side marker setup is that like I've explained, they see power from either of the two wires, which means the bulb can't be polar to work in this application.

The fender bulbs are a 2-wire bulb that are spliced directly off of the power to the front parking lamp bulbs. The factory parking lamp bulbs are incandescent and will let electrons flow through them either direction, so this works well. The side marker is spliced to the parking lamp (+) and the turn signal (+). During the daytime, headlights are NOT on, if you turn on the turn signal, the side marker will get power from the turn signal wire when the turn signal is on. The side marker as such, will blink in unison with the front bulb. The side marker gets its ground by being connected to the parking lamp filament of the front bulb. The side marker's ground runs through the front bulb, to ground.

When it's night time, and the headlights are ON, the side marker gets a constant power signal from the parking lamp (+) wire. It grounds through the turn signal filament of the front bulb. This works fine for a constant night time running lamp. When headlights are ON and you turn on the turn signal, the bulb sees 12V (+) on both wires (the parking lamp from the lights being on, and a blinking 12V from the turn signal wire. When the bulb gets 12V on both wires, it shuts off because it no longer has ground. Thus, the bulb blinks opposite of the front turn signals when the headlights are on.

So........

Get a non polar bulb if you just want to install in the side marker and have all work as intended. A non polar LED will work perfectly in the side marker with no issues at all, because it will be compatible with power coming at it from either wire, and getting ground on the other wire.

The bigger issue is when you go to put LEDs in the front grille locations. Remember the explanation of how the side markers get ground through the front bulb filaments? That no longer works when an LED is in place. No amount of resistors or flashers will fix this issue.

The fix for that is to rewire the side markers so that they are independent of the front lamps.

This is a good write up to fix that issue: LED Side Marker Mod. Essentially the fix has you rewire the 2-wire side marker to perform like a 3-wire bulb, while still using a 2-wire LED bulb. You use a small resistor to artificially dim the LED for a parking lamp setting, and then you have a full brightness turn signal where the bulb shines at it's normal brightness. This means you need to choose a bright LED for it to be a good choice. Overall it's a pretty cool mod but most won't bother with it. I did do it to mine just for the unique cool factor, but I get that most won't. It adds complexity and there is no real benefit besides using cool LEDs.

Once you address fixing the side marker, then you can put LEDs in all locations, and that's when you would want to use that computer controlled flasher. You can also use that flasher if you simply swap the tail lights or if you put a non-polar LED in the side markers.
 
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That brings up a funny memory about polar LED gauge lights. I bought mine through Amazon and they were rated 2.5 stars from buyers with most all comments saying 6 out of 12 lights didn't work. After reading a dozen reviews I came across one which said "If the light doesn't work, remove the bulb, rotate it around the other way and re-install it."

Sure enough when I installed mine several didn't work the first time but after turning the bulb the other way they worked as advertised.

The gauge lights are all push in not screw in.
 
Good to hear swapping back fixed your issue. I was pretty certain it would.

As for the flasher, unfortunately that will only solve one problem. LEDs cause several problems. WARNING: none of what I'm about to ramble about matters since you're staying stock anyways, but I may as well explain the deal and how it works for anyone interested.

LEDs draw very little power compared to an incandescent equivalent bulb. The flasher relay is built to blink when a certain amount of power is pulled through it, which is calibrated to how many incandescent bulbs are on the vehicle. On the YJ, the turn signal flasher (not the hazard, there are two total flashers) is calibrated for basically 2.5 bulbs since the front and rear bulbs pull about 27W each and the side marker fender bulbs pull about 12W. When you change to LEDs, you screw up the load, and the flasher stops working. On modern cars, it's computer controller and the computer will blink the flasher in hyperflash mode. So, the flasher you linked is for blinking the circuit properly when you have converted to all LEDs and no longer have the proper load for the stock flasher. The flasher you linked is computer controlled in and of itself, so it knows exactly when it wants to blink.

There are other issues with LEDs, though:

1) they are polar, like you experienced.

Most LEDs will only accept power in one direction, which means ground works on one pin and power on the other, and if the bulb is installed backwards in the socket, it won't work. In your case, the bulb worked half the time, but not the other. Flipping the bulb would have reversed your results. The problem for a polarized bulb in the YJ side marker setup is that like I've explained, they see power from either of the two wires, which means the bulb can't be polar to work in this application.

The fender bulbs are a 2-wire bulb that are spliced directly off of the power to the front parking lamp bulbs. The factory parking lamp bulbs are incandescent and will let electrons flow through them either direction, so this works well. The side marker is spliced to the parking lamp (+) and the turn signal (+). During the daytime, headlights are NOT on, if you turn on the turn signal, the side marker will get power from the turn signal wire when the turn signal is on. The side marker as such, will blink in unison with the front bulb. The side marker gets its ground by being connected to the parking lamp filament of the front bulb. The side marker's ground runs through the front bulb, to ground.

When it's night time, and the headlights are ON, the side marker gets a constant power signal from the parking lamp (+) wire. It grounds through the turn signal filament of the front bulb. This works fine for a constant night time running lamp. When headlights are ON and you turn on the turn signal, the bulb sees 12V (+) on both wires (the parking lamp from the lights being on, and a blinking 12V from the turn signal wire. When the bulb gets 12V on both wires, it shuts off because it no longer has ground. Thus, the bulb blinks opposite of the front turn signals when the headlights are on.

So........

Get a non polar bulb if you just want to install in the side marker and have all work as intended. A non polar LED will work perfectly in the side marker with no issues at all, because it will be compatible with power coming at it from either wire, and getting ground on the other wire.

The bigger issue is when you go to put LEDs in the front grille locations. Remember the explanation of how the side markers get ground through the front bulb filaments? That no longer works when an LED is in place. No amount of resistors or flashers will fix this issue.

The fix for that is to rewire the side markers so that they are independent of the front lamps.

This is a good write up to fix that issue: LED Side Marker Mod. Essentially the fix has you rewire the 2-wire side marker to perform like a 3-wire bulb, while still using a 2-wire LED bulb. You use a small resistor to artificially dim the LED for a parking lamp setting, and then you have a full brightness turn signal where the bulb shines at it's normal brightness. This means you need to choose a bright LED for it to be a good choice. Overall it's a pretty cool mod but most won't bother with it. I did do it to mine just for the unique cool factor, but I get that most won't. It adds complexity and there is no real benefit besides using cool LEDs.

Once you address fixing the side marker, then you can put LEDs in all locations, and that's when you would want to use that computer controlled flasher. You can also use that flasher if you simply swap the tail lights or if you put a non-polar LED in the side markers.
Wow, thanks for the detailed explanation/lesson! If I decide to go LED in future I’ll be back looking for this note.