So ,still working on this project car...trying to get automatic headlight switch to opporate. found the location of the daylight sensor. Can anyone tell me how I can test it without removing it? Not wanting to tear into upper dash to remove it unless I have to. If I do any advise on getting to it? Is it more likely that the problem is in the twilight sentenal circuitry? Does the manual light switch play a role in the auto function? Any help would be appreciated. Thanks

P.* Headlight come on only with manual switch.

My money is on the photocell sensor, I don't think you can easily test one though.
I am pretty sure you have to remove the dash pad to get to that sensor.
I could not find a part number for this, but I did read where somebody said they went to Radio Shack and bought an assortment bag of CDS photocells, and used the large one to replace theirs, not sure if that would work for you, but if so it will be a lot cheaper than getting the part from a dealer, I'd try salvage yards before a dealer.