All, I recently purchased a 2008 Trailblazer LS, car is super clean, runs awesome, and I love it overall. One thing that is odd is the lights inside flicker. I do not mean the slight dim you see when like the window motors are running, or when AC turns on, this is a definite flicker. The lights dont go out, but they dim and brighten fast. Its not constant, but happens enough to be annoying.

Any ideas? Thanks in advance!



2008 LS, 4.2l, 4x4

 

I had this issue with my old 2004 Buick Rainier. In the end, I had cleaned the throttle body, installed a new battery, rebuilt alternator (could have still had an issue), checked/cleaned all of the major grounds between the engine/body/frame/battery, as well as installed new grounds & power leads from the battery to the major components. In the end this all helped to greatly reduce the fluctuations, but it was still fluctuating some.

Supposedly there is an PCM update that helps this condition, but I was using a tuned PCM and didn't trust the dealer to not flash the whole thing back to stock. I was going to rewire the alternator to run off battery reference instead of PCM control, but ended up trading in the truck before I got to that point.

 

My trailblazer does this as well. Seems to be a common problem, It seems like nobody has found a real good fix for it.