Hello all. It's been a while since I have asked anything but I do read up every day. But I will get to the problem. It just showed up today. If I have my lights on, the third brake light is on but dim. At the same time it seems that the other brake lights are a little brighter. If I hit the brake all of them turn on bright. If I turn the lights off the third brake light is off too but then every time I push the brake the dash lights turn on dim and along with the fog lights and parking lights. As soon as I let off the brake the dash lights along with the others turn off. Does anyone have a clue what's going on? Maybe the brake switch? If it matters, it is a 01 cherokee with 219,000 miles. Thanks for any help. This is my daily winter driver and so far she hasn't let me down.

 

I just went out and it was still doing the same thing. But this time when I started it, it went back to being normal but I'm sure this issue will come back so I'm still open to suggestions.

 

You should get your alternator tested out. And the battery.

 

Thanks for your response. I do have a load tester for both so I will have to try it out in the next day or two.

 

No. The OP needs to start checking grounds for the tail lights and brake lights first.

 

Thanks. Do you know where the grounds are for the tail lights and brake lights? I just went out and checked it again and they are still acting normal but I don't know what tomorrow brings.

 

I would highly suspect a break where the wiring enters the rear hatch from the body.

 

Thanks for the response. I did find a few broken wires over the summer when I was tracing down why my rear wiper didn't work. I think I replaced three wires but I guess more could of broken since then.

 

Remove the tail light lenses and inspect the bulb sockets and connecting wires.
Follow those harnesses to the ground points.
Also check (remove clean replace with a dab of dielectric grease) all the bulbs.

 

Well thanks everyone for the help. The problem hasn't come back yet but today I put my load tester on the battery and both the battery and the alternator tested out fine. I also put a dab of dielectric grease on the bulbs and checked the wires by the tail lights. So for now I guess I will have to wait to see if the problem comes back.

 

You're getting good advice from MtnGoat. There was nothing at all to indicate a problem with your alternator or battery. What you are seeing is CLASSIC bad ground symptoms. That's where you need to focus your efforts.

It could also be an intermittently bad bulb or socket, but grounds are the first suspect on the list. Ground points should be made shiny clean, both on the body and the connecting ring. Don't rely on the screw threads for a good ground. A little dielectric grease there is also a good idea, AFTER they are shiny clean.

 

Thanks for the excellent info. Do you know where the ground locations are in the back? When I pulled the lights, the wires just run into the body.

 

I don't know off the top of my head, but follow them and see! Typically they are not far away.

 

Well I found the problem. I pulled both rear panels off and all the connectors( two on the passenger side and three on the drivers side) where all corroded. When I pulled the connectors apart to clean them most of the pins broke apart and even the one connector melted when it shorted out. So I cut the connectors out and used heat tube butt connectors on them. And even got a bonus out of the deal. My rear wiper now works the way is it suppose to. That wire and pin was all corroded too. There was two grounds on the drivers side that I did clean up. And if your wondering why everything was corroded, both rear fenders wells had rust holes in it and when I would drive in the rain and snow and salt it would all spray up in there. I also fixed the holes with some metal so no more water sprays up in there. Hopefully the pictures will work too.