'93 YJ won't start / battery good / no crank / dash has power

EvilRbt

EvilRbt

Member
Joined
Aug 16, 2022
Messages
31
Location
Los Angeles
Drove my YJ for about a half hour. Parked for 20 minutes. Wouldn't start. Almost totally dead.

Did a rolling start down a hill in 2nd and it fired up. Drove fine but CEL was on.

Parked it at the top of another hill to turn off and restart. Same thing. Almost totally dead. This time a hill start wouldn't work. Sounded like the engine was turning over at low rpms but wouldn't keep running.

Pushed to the curb. Now totally dead. Some power to the dash, LED headlights (I didn't install) oddly only have bulbs lit, radio worked, but no crank, no click.

Took the battery to auto parts store. They charged it up fully and said it seemed OK. I reinstalled and still nothing.... no crank AT ALL. Still getting power to dash etc.

Any ideas? Bad starter? Debating on troubleshooting further or having it towed to autoshop after New Year. I can do basic maintenance so if any ideas and not too complex, I can give it a shot.

Thanks, everyone, this forum has been awesome since I bought my Jeep about 18 months ago.
 
Okay, I'll give a shot at this. Someone else may be more helpful.

You didn't mention engine, but looking at the schematics, under the hood, there should be a 40 amp fuse (F4) that looks to give power to the ignition switch. I'd verify it is good. Start simple.

Then check and see if the starter relay (relay F) is good. You may be able to switch it with another relay (horn (Relay A) or something unimportant) if the relay is the same. If say the horn and starter relay are the same, just test the horn and make sure it works, then swap and test horn again and see if it cranks.

Here is the page from the web where I found some additional schematics for the underhood fuse/relay box.
www.autogenius.info

Jeep Wrangler YJ (1987 - 1995) - fuse box diagram - Auto Genius

Jeep Wrangler YJ (1987 - 1996) - fuse box diagram
www.autogenius.info www.autogenius.info

I haven't verified it's 100% correct. It's too cold and dark outside for me to go digging at my Jeep to double check.
Your relay box should have a diagram under the lid.

Good luck!
 
I'm not up on the Wrangler starters, but you may put the Jeep in neutral with wheels chocked and try to jump the solenoid (if possible) to further test and see if the starter is good or not. I'd do a search and see if that's a thing. I've also had auto parts stores tell me a battery is good, but it be too weak to do its job of starting a vehicle.
 
Okay...

Changed the starter today. Wasn't that.
Battery connection seems good, battery is getting 12.6v
Also seems to be sending power down the cable to the starter (tested w/ multimeter)
I swapped the starter relay with horn and didn't change anything.

When I turn the ignition, maybe a click (the first time at least) but no crank. Dash lights, radio etc. turn on.

Any other suggestions? Unreliable battery cable? Ignition switch?
 
I'm not a fan of just throwing parts at it without checking. Did you verify the 40A fuse in the relay box was good?
The big cable to starter will have battery power all the time. You gotta figure why the small trigger wire isn't sending.
Do you hear the fuel pump kick on when you turn the key but before you crank?
When cranking, do the lights all dim?

Check those cable connections. Both hot and ground. Not just at the battery. But the other ends too.

*****UNHOOK THE POSITIVE BATTERY TERMINAL BEFORE CLEANING THE OTHER ENDS****

I prefer to actually unbolt wherever they go to and wire brush or use a bit of sandpaper to make sure they are getting a clean surface, then snug them back down.

See if that helps.

If not, the next thing I'd try is jumping the starter with a screwdriver like this post states and see if something happens:
https://Jeep Forum/threads/yj-starter-relay-problems-or-something-else.3132569/

***edit*** dunno why this post is being stoopid and putting a space in that link. Remove the space between jeep and forum and add dotcom after forum

*******Note, make sure the transmission is in neutral if a manual.******

See if that starter will spin. If not, I'd recommend trying jump starting with a running vehicle and battery cables.
A battery showing voltage means nothing. The starter needs a lot of amperage to crank. If it starts when being boosted, then battery.

If that fails, the next thing would be directly connecting jumper cable from a known good battery to starter and seeing if it'll spin.

Actually, that linked post is a good walk through of what to check and basic troubleshooting.

Report back and let us know what happens.
 
Last edited:
Okay, tried jumping the solenoid on the starter this morning still wouldn't turn. I swapped out the battery cable and sure enough, fired right up. Even though I seemed to be getting 12V thru the cable, I guess it couldn't handle more than that when I turned ignition.

Only challenge I had was trying to get the connector off the end of the positive-ground cable so I could re-use and mount to the fuse box. That broke so I jerry-rigged it by clamping the ground wire between the broken clamp and the side of the fuse box. Sure wish they'd make these "universal" battery ground cables a bit longer too.

Thanks for everyone's input! Really helped me troubleshoot. In hindsight I guess I didn't need a new starter but the existing one was really old so didn't hurt to change it out for a new one.
 
  • Like
Reactions: ytradio
Glad you got it sorted!

Yeah, wiring can be interesting. They can show voltage, but be corroded enough internally to cause resistance issues with amperage flow.

If you haven't, go ahead and replace your negative cable when you get the first chance. It will most likely be almost as bad.
***edit*** I see you mentioned that.

I had an issue once on a fuel pump on a Dodge truck.
I changed the fuel pump out with no luck. Voltage was present at fuel pump, but pump wasn't working.
In my frustration, I bench tested the (now 2) fuel pumps. Both worked!
But when connected to the harness and tested, neither worked.
Made a basic harness and tied it in under the hood at a connection there.
After removing the old harness and cutting into it, it had so much green and white powdery corrosion inside and was so brittle, I was surprised it ran at all.
 
dead starter motor is the post. not the engine, as it push started. or gravity started ok
so learn this about electrics.
the meter (DMM is like 10meg ohm input impedance (resistance) (means zero load on the battery )
so if the meter reads, 12vdc it means gee the cells in the battery are not open or one or more shorted inside it.
only the load tester proves good battery.(click)
or the 2 man rule, one cranks (100+ amps flow) and the other uses the meter for voltage drop and yours did fail that
I bet.
bad battery, bad cables, bad starter, the meter will find them if you use 2 man testing. using the meter to find out of full 11vdc makes it to the 2 lugs on the starter, 11v is par voltage cranking, and the voltage drop is aLL INSIDE the batteries cells. 12.6vdc is rested key off voltage state of charge 100%
the starter can be HOT wired too, keys in pocket .
battery bad
lugs bad or just rusty
battery cables bad, mine were a wreck day one, and fixed first. DC Power must be good or you will get stranded.
starter bad
or any of those intermittent. (endless cases as we type on all cars.)
the cure is crank and test at the same time solves the riddle of , where is the point of failure. every time. (voltage drop tests)
 
Top Bottom