Thanks for the question.
Is this the old IDI 7.3 or the 7.3 DI Turbo?
Is there any smoke coming out of the exhaust when cranking? What color is it?
I started the truck and drove it about 20 seconds. I think the alternator went out and may have spiked voltage. The truck died. When I tried to restart it, the wait to start light did not come on and has not come on since. No smoke from exhaust. This is the non turbo 7.3 diesel. I do have 12 volt at relay.
Ok, check fuse 17 for the wait to start light. Replace if blown.
Check all fuses for that matter. Especially under the hood. Replace any that are need.
Then I would like for you to check for 12v on the BK/O wire going to the glow plug controller. If you don't have 12v there, you have a blown fuseable link. Repair.
Check for 12v with the key in the run on R/LG wire at the glow plug controller. If you don't have it there check for blown fuse "K" replace if needed.
Let me know what you come up with so far.