OK i have a 1982 trans am and my problem is when i turn the parking lights on everything works but when i turn the head lights on my dash Gauge lights go out i have looked at the fuse and the switch. i went out and got a new switch but it still does it

thanks

 

Maybe a problem with the dimmer control?

 

Check the potentiometer where the headlight switch is.. might be bad ?

 

look to the left side of the steering column as it starts to enter the dash, there is a metal reinforcement bar that runs under the dash, there will be two black wires bolted there, if there loose that will cause whats happening to your car, these are the dash harness ground wires