The brake lights on my envoy are not working. The third light is working. I replaced the brake switch and the bulbs and the lights still don’t work. My hazard lights are working. Any ideas what I should try next?
If you feel guesswork is a valid path to solving a problem, try throwing a BCM, body control module, at it…Todays car, the lighting is all controlled indirectly through a “computer box” called a BCM. But first check the fuses…MUCH cheaper…
My supervisor had one of these as a company car. The dealer worked on the truck off and on for years trying to fix the left side brake light, which refused to work.They never got it to work, and my supervisor had a letter in the glovebox from GM explaining the problem if he were ever to be pulled over for it.
Are your brake lights and turn signals on a shared circuit (brake light bulbs flash for turn signals/hazards)? If so, your turn signal/multifunction switch may be bad. GM is notorious for routing the brake lights through the turn signal switch, leading to this exact problem. The turn signals and hazard flashers will work fine, as will the third brake light, but the side brake lights will not work. Their mid size FWD car line from the mid to late '90s is famous for this issue.
Most of todays vehicles have different bulbs/lenses for the turn signals/brake lights…The latest cars have all gone to LED lighting…
Is F34 good. It feeds the brake lights.
If fuse 34 is bad then check the trailer hitch wiring if you have that feature.
Where is the brake switch for 2003 gmc envoy