Hi all,
I have an 80 vette with the courtesy light timer on board. Here is the description of my problem.

Courtesy light stay on all the time.

when I unplug the timer circuit board they will only come on by turning the light switch all the way left. But then opening the doors will not turn them on.

I have checked the door switches. They seem to be fine.

Does any one know how to check the circuit board?

Thanks in advance

Hop