I have just put the entire front clip back on my 69 Camaro and found that I have an issue with my left turn signal. The left turn signal blinks slow with the head lights OFF and the right turn signal is operating perfect. When I turn the head lights ON the left turn signal does NOT blink but the right turn signal is operating perfect.
I have replaced the flasher unit, fuses, light bulbs, checked the ground wires, cleaned the driving light sockets and contacts on both the sockets and bulbs.
About the only thing I have not checked is the turn signal switch in the steering column.

Any suggestions on how to find and correct this problem?

Thanks, Abestoy!

 

Ground faults (corrosion) accpunt for most electrical issues on an older car. There are several grounding straps on a camaro. Make sure you have good ground connections.

 

Driving light sockets? Do you have aftermarket lighting?

As mentioned before, ground faults will throw symptoms like this. When I put on my fiberglass front end, I chased light faults for what seemed like decades.

If you crossed the wires between your headlights and your turn signals, you might get something like this, but they are on separate circuits all the way from the switch. Since the right side works normally, the problem is not between the battery and the switch. The ONLY thing the head and turn lights have common is the ground.
If all else fails, try moving the ground wires apart so that the headlights are separated from the turn signals. Don't mess with the right side at all - you may need it for a model to copy if all else fails.