Drove to a VW show this morning and when I turned the car off to set up my booth, would not restart.
All electrical is dead but battery shows over 12v.
When key is turned in ignition, none of the gauges register although the fuel gauge does move a bit.
Lights do not work.
Hazards do not work.
Fuel pump not working (is on a switch)
Any ideas where to start looking?

Thanks!

Sounds like a bad ignition switch, but double check the battery leads to make sure they didn’t vibrate loose or are making a poor connection.

Did it “fix” itself once cool by chance?

First thing, clean and tighten battery terminals. Gotta do what is quickest first in this situation. Grounds. Hoping you get lucky before you have to break out the multimeter.
Could be ignition switch, but that usually fails on crank (starting only).

First thing I did was check connections at battery. All good.
Former race car so electrical is a bit “custom” and lights, etc
Lights, fuel pump, etc all usually work without ignition switch on.

Still sounds groundy. Multimeter. Power to the switch panel? We could only wish a fuse is blown.

A guy here at the show knows electrical systems and is going to help me.
Thanks for the suggestions. Should be something easy once found.

Ended up removing both battery leads, tightening the clamping bolts, reinstalling and that seems to have fixed the issue.

I made it home

Thanks to those who chimed in.

Ugh. The thing was the fucking thing. Basics. Learning lesson!
Always listen to experience, even if it's not this answer.
You don't "check" battery connections by looking at them. You take them loose, use a tool to clean the terminals and the posts, and clamp them back clean.