I have a 2002 Blazer. Left turn signal only works with the headlights off. Any help would be appreciated. Thanks!

 

First thing I would do is remove the headlight ground on the radiator support, clean it up, and make sure it's making good contact.

 

Tom A
I located 4 grounding wires from the light harness that attached to the core support. One wire came from the negative terminal of the battery. After cleaning all four connections, I checked the connections for ground. All have good ground, but I still have the same problem. I checked the left parking light socket for proper ground connection and compared it to the right light socket. Both have the same grounding. I'm ruling out a harness issue since the turn signal works fine with headlights off. Any chance it's the headlight switch?

 

Sounds like one of the filaments on the bulb shorted to the other. I would try a new bulb or swap them left to right to see if the problem follows.

 

The problem stays with the driver's side after switching bulbs.