I have a 1994 XJ 4.0. The other day I got stopped by a friendly cop who told me that all 3 brake lights were out. I started researching and figured it was my brake light switch. I replaced it with a new one but that didnt fix my problem. I can't find my specific fuse because there are a few fuse boxes that I found that don't match up to mine. Is there a connector towards the rear that would cause my brake lights not to work? If anyone has any ideas I would appreciate because Id like to have brake lights.

 

There may be a maxi-fuse under the hood that protects the brake light circuit. My '87 and '92 did not have the third brake light, so my Jeeps are probably not exactly like yours.

You may have a bad ground somewhere that is in the dedicated brake light circuit.

 

Yes all dash lights work, all lights work except those.

 

After I made my first reply, I realized the dash lights and the rear taillights are on the same circuit, not the brake lights.

 

Any idea what other circuit the brake lights would be on?

 

There is a Molex connector behind the driver's side rear quarter panel that attaches the rear harness to the main harness. That connector is prone to corrosion due to moisture. It's unlikely that a problem there would affect just your brake lights but back tracing from there to the fuse panel/switch is the easiest way to locate your problem. I didn't say it was easy, just easier. Welcome to electrical troubleshooting.

 

Would I be able to reach this by just taking the driver side taillight off and checking there?

 

I had the exact same problem. It turned out that the third brake wire was shorting out at the hatch, where the wires break from repeated movement. That would pop the fuse and kill all three lights. So you might look there.

 

I live in Michigan. My drivers rear quarter rusted a hole in it... ALL the mud and road grime just funneled up into that area. All my lights started acting funny. You have to take off your spare. Unborn the 4 bolts for the spare carrier. Undo about 6 screws to pull forward that whole plastic piece in the back. Takes about 10 mins.

There's a whole plastic junction there. All your rear electric wires thru plugs. Easy place to test. Might want to buy a can of electronics cleaner before you even open it. Might be your issue. He's right about it at least being a place to start. If no juice back that far, 20 mins well invested in diagnosing it.

 

Thanks Billy, perfect description of what he'll need to do back there.

 

I actually used a bug sprayer with soapy water to flush out 5 pounds of mud. Then filled it with house insulation foam on an aluminum base. Total redneck fix.

 

That sounds promising, where was the wire located where it split? Im not with my jeep right now but I will check tomorrow.

That helps alot, I will definitely check this when I get home tomorrow. Thanks! Ill let you know if this was my problem

 

Right where the wires pass from the body to the hatch. There's a rubber boot between the two. You can either try to pull the rubber tube out ( I couldn't manage to) or cut it open and look at the wire. There's likely to be a decent amount of cracking. My XJ is a '99, not sure what differences there may be.

 

If this was the problem would it cause a fuse to blow? Because I looked for a diagram and couldnt find the fuse that went to it. Does anyone know what fuse number it would be in a 1994 Cherokee SE? Because I don't think it had a fuse to begin with after checking..

 

Mine certainly did. The fuse is in the PDC under the hood.