Ok I need some help with the dome light turning on when the doors open. Mine do not.  I get the buzzer when I open the drivers door and the keys are in the ignition but I do not get any interior lights when the doors are opened. I cleaned both door contacts and  the dome lights work but cannot  trace the path wether its a breaker fuse or relay but mine are not working.  I see something about the dome light delay relay... but not sure if that might prevent the dome light from coming on or its just the timer when the light is on. but maybe its the relay...any heklp would be greatly appreciated. Thanks mark

The courtesy light timer will turn the lights on...if it's working properly. It will also keep them on all the time if it's not working properly.
The delay module should be just under the glove box, behind the dash.
There is another thread here on the delay timer module...somewhere...

On my 79, it's is under the drivers side dash near the steering column - orange box.

Found the box jsut didn't know if it would cause the lights not to come on in the first place or just alter the time they stayed on, found it and will check but might not know until I get a new one$$$$$ in there  to see if theat will turn on the dome lights. Thanks again seems like they are $85 unless you can order them somewhere else?  Thanks BB78

There was a post here a while back where mknapp7879 described the troubleshooting/testing routine for the timer. It's been a while, so the search may take a while. I'll see if I can round it up...

Here's one...I'm still lookin....

And check the Last Post on this thread...
Adams' Apple2010-01-20 11:15:40

Sounds to me like its gotta be in that Mercury switch.

ok just to review the mercury switch?? the dome timer under the steering column or the main light switch on the inst panel left side, the only mercury switch I'm aware of is the one for the hood light??? confirm please...I was leaning to the dome delay timer for $85.... but did not think this would prevent the lights from coming on with the doors open just affect the light staying on once you close the dorrs for a period of seconds..mayve it controls both.