In my 1988 camaro the left turn signal either doesn't flash at all or it flashes very slowly. On the inside when I turn on the headlights and the gauge lights come the left signal indicator stays dimly lit up whether I'm using the signal or not. What could be causing this?

 

Try replacing the Flasher under the steering column.

 

When the indicator is always lit, it means that a ground/common is disconnected at the turn/park lamps on that side, usually a bad socket. The current from the parking filament on the left side (in your case) goes through the turn filament to the indicator bulb, instead of going to ground. That is also the reason for the slow turn signal on that side. You probably also have a somewhat dimmer parking light on the left side, as a result.