Brake lights cause dash lights to stop working
The car is a 67 RS/SS camaro. It probably doesn't matter but it has a 350 and th400 auto transmission.
I was having problems with my tail light/turn signals/ brake lights which I figured out was being caused by a variety of problems including bad grounds, bad bulb sockets, and a bad turn signal switch. I made sure the rear lights were grounded well and fixed the bulb sockets. I also replaced the turn signal switch and got all the rear lights working correctly.
When I drive with the headlights on, everything will work fine for a while and then after about 5 minutes the dash lights, tail lights and brake lights will quit working. If I then turn off the headlights for a few minutes every thing will come back on and work fine for a while again.
The symptoms seem to happen when I use the brakes but not immediately after they are touched. It seems like I have to sit with them on for a while (like sitting at a red light). Also it seems like if I make sure that the turn signal is on when the brakes are used, everything works fine. If I don't touch the brakes the lights seem to work fine although it is an intermittent problem so this could just be coincidence.
I'm pretty confident it is not a ground problem because i have run a ground wire straight from the cluster to the (-) post on the battery while the dash lights were not working and it didn't affect the problem. Also, I used a multi meter to test the gauge cluster both while the lights were working and after they quit and I found that I am losing power to the cluster which is causing the lights to quit. I thought the headlight switch may be the culprit so I changed it but it didn't help.
So I know I am losing power to the gauge cluster but I don't know why or how to fix it. I know that when you have the turn signals on and hit the brakes it takes the brake light circuit out of the picture so that leads me to believe that maybe there is something wrong with the brake light circuit. Maybe a short or something? However, if this were the case, why is it not blowing the fuse and why will it start working if I let it set with out the headlights on for a few minutes? Is there a relay or circuit breaker in there somewhere that heats up, quits working, and then starts working after it cools down? Also all the lights seem to work fine when the headlights/tail lights are not on.
Anyway, sorry for the long post but I wanted to get all the details out there. I have searched and stared at wiring diagrams until I went cross eyed but am not sure how to troubleshoot this thing. Also I am not very good at electrical stuff. If anybody has some suggestions, I would appreciate it.