brake lights that don't work when lights are on

[jennster]

what is up with this?!?! the brake lights work just fine, until you turn the actual lights on, then my left one just stops working once the brake pedal is pushed down. anyone have this happen and find a fix for it?!?! thanks!!!

[JeepForever]

The somewhat obvious answer is, "sounds like an electrical problem". Perhaps with some more info we can help troubleshoot it.
* Have you replaced any light bulbs recently?
* Did it just start happening? (or is it a 2nd-hand car that you just acquired?
* What year, make, model?
Sounds like it might be a short circuit, but we'll see if we can help find where it's coming from.

[jennster]

Originally Posted by JeepForever

The somewhat obvious answer is, "sounds like an electrical problem". Perhaps with some more info we can help troubleshoot it.
* Have you replaced any light bulbs recently?
* Did it just start happening? (or is it a 2nd-hand car that you just acquired?
* What year, make, model?
Sounds like it might be a short circuit, but we'll see if we can help find where it's coming from.

hi there! it's a 2000 jeep grand cherokee laredo. the light bulbs have nothing wrong with them. replaced, and the same thing happens. i've had the car the whole time- it's happened NUMEROUS times.. then literally all this crap stopped happening once i hit 100k miles. but now has recently started up again. it seems like the brake light isn't actually lighting when i step on the brake- but the light part is. wait, that makes no sense right? are there 2 light components to the brake light? well only 1 of them is lighting up. it's weird.

[Cam7]

Sounds like there is a short in the the Tail-Brake Light Assembly probally the socket where the bulb fits. Whwn you turn on the Lights it is too much juice so only one will work shorting out the other. Take a good look at the wirring going back to the Light Ass for any breaks or bare spots.

[JeepForever]

Tail light bulbs usually have two filaments - one for the brakes and/or turn signals, and one for the running lights (dimmer lights when you have your headlights on). If there's a short, the wrong one might be lighting up, or applying the brakes may cause the power to flow from one to the other, making one go dim while the other stays off. An electic tester on each wire might help troubleshoot this (have someone in the car apply brakes, turn signals, & head lights, and see which wires get powered up).

[gmusillo]

I found this on another website.
It worked on my 2000 JGC.

1st Jan 2005, 14:02 I own a 2000 Jeep Grand Cherokee and I too had the same problem on the left tail light/brake light. Thanks to this website, I've regained my sanity (and stopped changing lightbulbs). Additionally, I was not going to pay for a part unless I absolutely had to, and I was able to repair the light with info from this website. In return, I thought I'd post how I did it.
1.) Remove the tail light assembly. Most of you know how to remove the light assembly if you've changed bulbs, so I won't cover that.
2.) disconnect the wiring harness by sliding the red locking clip to the side in order to press the side of the male connector and pull apart.
3.) Once you've got the tail assembly away from the vehicle and on a bench, remove the light socket for the tail/brake light. The top socket on a 2000 JGC. You will see 3 silver contact points inside the black plastic ring. 2 are grouped together and there is one that is opposite of the 2. The one by itself is the ground; the other two are the contacts for the tail light and brake light. The problem lies with the ground connector. (BTW, I tested continuity with all lights and contacts including the turn signal and the reverse light to verify that the circuit board itself was good, and it was).
4.) clean all contacts with a Q-Tip and some sort of contact cleaner - rubbing alcohol will work.
5.) You should notice that the ground contact is depressed into the plastic and the plastic itelf is slightly warped down. I was able to use a small pair of needle nose pliers that have a 45 degree angle to press up on the contact from underneath using the opposite lip of the hole as leverage (very carefully). Once it had moved up a bit, I was able to wedge a mini-flathead screwdriver in between the metal contact and the plastic to force the contact up even further (again, very carefully). Once it looked even with the rest, gently reinsert the connector and test. You can insert a flattened (one-sixteenth inch thick, no thicker) piece of solid copper wire about the width of the black plastic ring under the contact. re-insert the bulb assembly and give it a try.

Hope this helps...

jrdahle@yahoo.com.

[bakfuwarrior]

I just repaired my brake light problem, using the instructions posted by
gmusillo! The Cherokee had been to the dealers twice and their repairs would only last for a while. Also, I forgot the $35 charge by the dealer.
Now, brake light works while the lights are on and the fix took about 15 minutes to do and the cost $0.