Need your input on an electrical gremlin.

'79 model

I've got a short that will drain my battery within 48 hours. I've narrowed it down to the courtesy light circuit by pulling fuses to find the bad circuit.

1. I've checked my delay timer and the short is still there with or without it connected. The 5 second delay also works fine. So I don't feel the timer is the issue. Question though---are the interior lights suppose to fade off or just turn off with a 5 or 6 second delay???

2. I've checked all the wiring in the center console for any bare wires or shorts-everything seems fine there.

3. I've traced the wiring harness from the switches to the lights and see no bare wires or obvious bad spots.

4. The glove box light works fine.

5. Now the weird stuff-
a. The interior courtesy lights do not want to come on with the doors open if the engine is turned off. They will come on at first with the doors open when I initially hook up the battery, but once they time out and turn off, closing and opening a door does not turn them back on.
b. yet When the engine is running, the interior lights function as they should, turning on when the doors are opened. (issue a is not an issue when the car is running) ???
c. When the car is turned off and the interior lights don't want to come on, they will come on when manually bypassed with the headlight switch rotated to on. The headlight switch will manually turn the interior lights on any time, wether the engine is running or not, wether the doors are open or not...

Am I fighting a bad headlight switch? Or do these symptoms point out something else?

I'm baffled.

Appreciate your input.