on my k3500 it has some issues with the wiring. when i have the head lights on and you turn the turn signals on left or right the voltage drops from 14 to about 9 each time they blink. and when i hit the high beams it stay about 11 on the batt gauge. but ittl turn off my radio and it comes back on. anybody had this problem before its a 1990 88-98 body