All my interior lights work properly when the doors are opened and also stay on for the required delay time after the doors are shut. They do not, however, come on when the headlight switch is rotated counterclockwise all the way. I am suspecting that the headlight switch is defective. The only thing is that I noticed in the wiring diagrams that the headlight switch is connected to the delay timer unit also. Is there a chance that the delay timer could be the problem? Is this a common problem? How can I check for sure? Any feedback would be appreciated.