So this is whats happening.I'm having a problem with my brake lights not coming on.not the third light just the other two.The deal is when the car is stationary all the lights work as advertised with the headlights on or off.
even if the car is in gear fwd or reverse the lights work.But...when I drive the car the only the single spoiler light works.when the headlights are on the spoiler light only comes on,and when they are off no brake lights....WTF!!
The fuse is good even though this is not the prob.Not to sure what to check any suggestions....or if U have seen this before..thanks.
car 99 Trans AM

 

My old car (1994) had a bad ground when that was happening. I regrounded and no problems, it should have a ground under the carpet, between the two tail lights.

 

Usally any problem back there will be due to a bad ground, I had tons of problems with that on my 93