I have a 2003 Chevy Trailblazer LT with the 4.2L I6 auto trans and 220k miles. It does a thing when i step on the brakes sometimes the right turn signal on the dash illuminates slighty. When that happens, on the outside the reverse lights slighty illuminate. This comes and goes. Doesn't always do it. Also anytime its doing this if its in park there is a loud click when I step on the brakes also. The clicking only happens if the lights are acting weird and im in park. I've replaced the taillight housings and bulbs. Also replaced the turn signal relay under the steering wheel. When I replaced the relay it stopped for maybe a month but the problem has returned. Twice when doing the weird light thing when coming to a stop its died with no warning, but started right back up after. No engine codes either. Thank you so much.
what's the best way to find a short?
Scotty only answers once.
You need to dig out the wiring harness for your brake lights, and check the ground connections. They're probably rusted out.
Do i just have physically look at each wire?
Yes. Start with ground. If that's good then check the others.
Can I use a multimeter at the taillight or something?
Sure. probe the resistance between negative in the bulb socket and the vehicle chassis. A high resistance tells you the ground is poor, but it won't show you where to find it. I think it's going to be pretty obvious visually if you just follow the black wire. It's almost guaranteed that a 24 year old vehicle is going to have corrosion.
schematics are on charm.li if you need them.
@imperator thank you very much. Sounds like i definitely have some work ahead of me lol
It's not that bad. The interior paneling usually just pops out. maybe a couple of screws.
Well you either have a short and the brake light switch or the wiring somewhere where it's feeding back. Realize it can be a short in the power wire or a short in the grounding wire. GM products often have grounding wire problems
@scottykilmer what's the best way to find a short? Do i just have physically look at each wire? Can I use a multimeter at the taillight or something?