Brake Lights not working.

[m79ded]

Hi

I have a weird issue that I need help with on my 79 Magnum.My brake lights don't work and to add some confusion to the issue,when I do step on the brake pedal the interior door lights and interior quarter lights go on. This happened a few months ago and I changed a burnt light tail light bulb and problem went away. Well it came back and this time I just can't figure it out. I know the brake switch works but after that I'm lost. The only other thing I done this year to the car is add a tach but I splice into a dash light source for that. Any help would be appreciated. It's a mystery to say the least. Thanks

 

[PurpleBeeper]

You have wiring that's crossed for sure & the first place I'd look is at the 6-prong (or 8-prong?) plug leading to the tail/brake lights. It's right behind the driver's kick panel, near the emergency brake pedal. Pull out a wiring diagram & a multi-meter and start looking for those crossed circuits.

 

[Shorthorse]

First of all I know nothing about 79 model year wiring and can not seem to find any info online.
But, earlier Mopars had constant battery on the interior /courtesy lights and were activated via a switched ground while the brake lights were activated via a switched battery. If that's still true in 79, depressing the brake would not turn on the interior lights. When things don't make any sense, check your grounds, all of them.

 

[m79ded]

First of all I know nothing about 79 model year wiring and can not seem to find any info online.
But, earlier Mopars had constant battery on the interior /courtesy lights and were activated via a switched ground while the brake lights were activated via a switched battery. If that's still true in 79, depressing the brake would not turn on the interior lights. When things don't make any sense, check your grounds, all of them.

Hi I found the culprit it was a burnt fuse. I didn't expect that because I changed the fuse a few months ago. I will definitely clean all the grounds as suggested and put back the kick panel carefully. What threw me off was the interior lights going on. Thanks purplebeeper and shorthorse for your help. I really appreciate it very much.