I have been having this issue for awhile now and was wondering if anyone else this same problem. I have a 2001 chevy blazer lt with over 280,000 miles original engine and trans. Just thing to see what solved this problem for everyone else. voltage gauge drops when turn signal light is on. Thanks in advance!

 

Hows the battery and alternator?

 

Optima red top and a dr44g alternator that's good. This has been an issue from the time I purchased this vehicle in 2015 but never really worried about it until now. This is the same with or without a system in it I must say

 

Is it a big drop? Or just moves back and forth a little? I've always seen the needle move, but was never a problem. I don't think it is...

Only the signal? Or other lights as well?

 

Moves back and forth a little and no it's not a big drop