Thank you for this diagram. It does clarify some things for me. I have to wonder if there's a chance the clock may come back to life once the grounding issue is solved. Is that possible?

you may still have problems with the door switches, but keep in mind that when the headlight sw is turned CCW it puts a ground to the white wires. the door switches are not used at that point.

The delay timer wasn't used until '77. 
My bet is the wire terminals AT the door pin switches are bad. The white wires have TINY terminals that fit thru a plastic insulator at the pin switch, and are then bent over. When the switch is closed(door open), the terminals make contact with the metal switch housing, creating the ground for the lights. Those tiny, bent terminals fall off over time. Sometimes, the wire will fall off, too, but most of the time, the terminals stay put, and LOOK like they are good. The only real way to check is to unscrew the switch and have a look-see. You can ohm the wires from the socket to the pin switches, and they will most likely check out fine, since grounding the dangly wire lights up the one bulb on the other side of the car...that tells me the wiring itself is prolly otay. If you ohm from the white wire to the chassis(or battery) with the door open, I bet you find there is no continuity...
I have made terminals for these switches before out of other flat bladed terminals, so they can be fixed if yours are messed up. The one on my driver side on the '74 was, but it ain't no mo.
(btw....this is a replacement switch, and not made exactly like the originals)



And Rich...if ya snooze, ya looze!

|UPDATED|7/31/2013 10:34:33 AM (AZT)|/UPDATED|

So this is why when I run a ground wire to the switch housing nothing happens. There is a break (probably) AT the switch and probably having to do with those nasty little terminals.

By Jove, I think you've GOT IT! 
Yeah...that's what Imma thinkin is the problem...you've pretty well checked everything else, and it all seems to be in good shape. Being able to ground the dangly wire and have lights is the key. Even so, the courtesy lights should come on when you twist the headlight switch all the way....that might be a different issue with the headlight switch itself, but...one problem at a time...
Hang in there....we'll git ya lit up like a Christmas tree a'fore ya know it!

Well, tonight will be the CCW test of the light switch. Turns out one of the courtesy light sockets was empty, another corroded and the one in the back had the wrong bulb installed! So it's not much wonder that they didn't come on.

I had to replace the door switches in my 72 convertible.  Lights worked properly after that.  No delay timer on my car.

Hey for me this is fun. I think its more fun helping you than if I had to do it on mine. only my fingers are getting tired my back and old bones are not whining at me

You know you're not far from me. We gotta meet up somewhere soon. Aren't you pretty close to the Chateau St. Michelle winery? A bunch of us BSU Bronco fans make the trek over there once in a while because the winemaker is one of us.

Dave, we're not making fun of ya or anything like that. But...I do have a little chuckle knowing it's someone ELSE goin thru it. Trust me...we've ALL been where you are at some point, and we've all got the scars(physical and metal) to prove it! It's like a Classic Corvette rite of passage....everyone must do it.
We enjoy helping others thru issue like this...it's why we're here. We kid around, and have fun, but in the end, it's all about helping others. If we can help get and keep another Classic Shark on the road, it's all good!