A new problem cropped up the other day. Neither the left nor the right brake lights are working, but the taillights and turn signals are fine. The CHMSL works. The bulbs and sockets are new, as they were both very scorched. I replaced the brake light switch and no change. The rear chassis grounds adjacent to the taillights and the one near the battery are tight and clean. I'm at a loss here

 

Fuse #9 on the BCM?
What caused the scorching? Was it fixed?

 

I don't know what caused the scorching, other than to say that every wedge-base light bulb socket on the car had the same scorching and the taillight housings are deformed from heat.
I checked fuse 9 on the BCM and it's fine, but I found that the bolt that was supposed to secure the BCM was missing and that there's a fuse tap on the sunroof going somewhere up into the dash. I installed a bolt to secure the BCM, and now I'm just hunting for more wiring damage done by the previous owner

 

Is there an after market radio? Trailer hitch wiring?

 

I did some further exploring inside the dash and found the stereo harness was badly backed up and a radio harness was "spliced" in by twisting wires and taping them. I didn't realize how bad it was when I installed the warning chime module. I also wound two lengths of 16 gauge wire running from under the center console to the vicinity of the rear amplifier, but not actually connected to anything. This is gonna be fun

 

If the radio was installed without the module the radio needs a source of "switched" power, thus the tap on the sun roof fuse. With the module there is no need for a tap.
I suspect that someone that had experience with 20th century wiring thought they knew what they were doing. I would completely remove the radio and re install it correctly. The pink wire powers the antenna and the amplifier.

 

Another car vandalized by a radio hack job.😡

 

People to cheap to get the correct parts for their head unit