I have a 91 suburban with a weird taillight problem, the brake light, hazard, and turn signal are not working at all, but the taillight works. Brake light switch was replaced by the owner (per Autozone employee instructions) and problem is still there. I checked for signal from signal light switch, signal is good. if you activate the turn signal, it blinks normally not fast. the front flashes, but not the rear. same deal with the hazards, everything flashes except the left rear. and the bulb was also replaced by the owner, removed and checked the new one myself. flasher is good (eveything else is working) turnsignal switch is good (front is flashing, as well as everything for the opposite side) Any suggestions??? I am about to pull my hair out on this one!!

 

The flash may not vary with the load. Some older flashers flash at a constant whether loaded or not. Try replacing the bulbs.

 

already checked the bulb...

with test light in hand, I checked the socket for power and didn't get anything. Powerprobe told me the ground was good, but not the signal wire.