No brake lights when head lights on.

[wandrinwizard]

Hello all, I am new to this but am going nuts over this one. I have a '99 Jeep Grand Cherokee Laredo. The brake lights work fine when the headlights and running lights are off, but when I turn the lights on the brake lights will not work and makes the rear running lights go out. Please help someone!!

 

[zatog]

Well there could be so many different things going on with your lights. My guess is that your wiring going to your tail lights is shorting out someplace. Have you checked your fuse box too. There could be a broken fuse.

 

[radsterdeez]

You could also try bad earthing. I had this issue with my 2005 TJ. My turn signal lights would also start flashing fast or not at all. Check all earths for rust. Start by taking your brake lights out and check them. It is earthed through the actual casing of the brake light. Take it off and check for rust. That place is the most common due to water might be able to leak in behind the casing and the body. I just took it off cleaned up the bolts and the casing with sandpaper and now it is working sweet. Hope this helps.

 

[superj]

also, might get more help from the cherokee guys. we can offer assistance but not all of us own cherokees and our system might be different enough that what we tell you to check might be different then what you actually have on your truck

 

[TerryMason]

Moved to the Cherokee section.

I agree with checking the grounds. Turn the headlights on, and take out each brake bulb and check for corrosion.

 

[extra-medium]

i was told that all the lights run through the headlight switch so that might be going bad

 

[wandrinwizard]

Got it fixed. had to swap light sockets around on the passenger side and completely replace the driver side light assembly. I thank all for all the help.