Dash Wiring Issues

Apologies in advance for all the Mopar rookie questions :-)

I'm trying to chase down a dash wiring issue in our '64 Dart, specifically there are no dash lights and the fuel and temperature gauges sometimes decide to take a random little vacation together. I downloaded the wiring diagram for the '64 Dart from mymopar.com but it's incomplete. Is there another good resource for wiring diagrams? Are there any known / common fail points? Also, is there a dash ground somewhere? I looked around but didn't see one, unless I overlooked it. Totally possible, me with my bad back trying to work under there.....