On the way to work this morning I just do happened to look in my rearview and noticed my brake lights were shining off my rear tire carrier. Thought it was odd so I tapped the brakes to see if it got brighter and they did but only by a little. When I got to work I got out while it was still running and yep, my brake lights are stuck on. So my first thought is it's probably the brake pedal switch. But here's the thing. When I turned my headlights off, they went off and functioned normally. I cycled my headlights on and off a few times and the brake lights came on still. Even my third brake light at the top of the rear hatch is on. So, should I be looking at something being shorted? I read a thread on XJTalk where a guy had his brake pedal switch need adjusting and his gas mileage was going down as well. Turns out he found his torque converter was disengaging due to the switch needing adjusting. Sticking his foot under the pedal and bringing it back would cause it to engage normally. He could also tell by the RPMs it was running. I tried this while I was still on the way to work before I searched anything and that doesn't seem to be the case for me. Didn't notice them go out when I tried this either. As of now they are off so I won't have to worry about my battery running down. They only stay one when my headlight switch is on. Sound like a short somewhere to you guys?

 

Check your rear bulbs, (see if a filament is touching inside). Also if you have trailer wiring see if its rubbed and shorting.

 

If it was a bulb, would one filament touching cause them all to come on?

 

Yes. it will back feed the circuit.

 

I'll take a look when I get home. At least they still function normally with the headlights off. Maybe I'll just buy new bulbs and put them in to be sure. New set only costs a couple bucks anyways.

If it turns out thats not the problem I guess the next step would be the wiring?

 

Look for a bad ground.

 

It may be in the back somewhere. Just saw on the way home today that my gear shifter lights come on along with the odometer dimming out like turning the headlights on. When I gets darker I'll take another look to see what all comes on.

 

Pretty sure it's a bad bulb as has been mentioned. Similar happened on my grandfather's car, but problem was wrong bulb type. He would hit the brakes and the side markers and night-time interior lights (dash, HVAC, etc) would turn on. Comical. Not exactly the same, but makes sense if you have a filament that is touching. Replace all bulbs and report back.

 

So before I went and bought new bulbs I tried taking them out to see if the interior lights still come on with all the bulbs unplugged. And they still do. I even took out all 6 bulbs for the front turn signals snd side markers. I also looked a couple ground points behind the rear drivers side panel cargo area and they are clean with no corrosion. So where else should I be looking?

 

.

 

Went out to look at a couple more things today and my battery is dead. So looks like something is shorting out and running it down.

 

At this point would it still be a ground fault? I've only checked two ground points so far and they are clean as can be. Is there a list of all the grounding points so I can just go through and check all of them?

 

So yeah I know it's been a while but I think I found the issue. Passenger side behind the cargo area panel there's a connector that goes to the outside for the brake light. I unplugged it and the problem goes away. It was corroded so I cleaned it and it still does it. I got my meter out and started checking pins to see if any are shorted. Found 2 that are. But I don't know what they go to. Anyone have a working diagram or anything I can reference to see what they go to? Google wasn't much help since all it shows me is the part that's on the light itself.



It's the female end that has the short. The make end I didn't see anything when I checked it. The side that only has the two wires are shorted together. The side with 3 wires seem to be fine.

 

You're getting closer. Trailer wiring on this Jeep?

 

Found it. That harness had two wires that were shorted together. I don't like the way it's fixed but I just cut out the connector and soldered each wire together and heat shrunk them. The connector was actually emitting a small amount of smoke while the lights were on. After soldering them all together it works fine now.