Help revive my first truck :( electrical issue

[thetaurean]

Hey everyone! I've got a 1996 1500 and it won't start. It used to run/work great but I took it to a shop that kept it outside for ~14 months (long story) and I think some animals got to it.

When I went to pick it up it wouldn't crank at all.
- The dash and all lights work but the radio and blower motor do not.
- The A/C compressor does kick on when the blower switch is in the A/C range
- When turning key to start, the dome lights / headlights turn off like you'd expect

The mechanic at the shop bypassed the starter and fuel pump relays in the fuse box, and after that the truck started and ran fine. I tried to limp it to my shop at home like that, but on the way the truck cut off almost like it lost spark or fuel. I towed it home and it's been sitting in my yard since.

I've confirmed that the fuel pump comes on when I start cranking, but that's as far as I've gotten really. What should I check next/first? I'm thinking I need to:
- double check all the grounds (physically and continuity with multimeter)
- somehow verify the integrity of the fuse box
- investigate all wiring pertaining to blower motor searching for animal damage

I'm hoping someone can shed some light on terminals to probe and opine on things that often fail that could be my issue.

 

[tron67j]

Maybe a relay has gone bad since the bypass got it running. Unfortunately, checking every wire from connection to connection is the best, but most laborious thing you can do first. That will eliminate a huge possibility, especially with it sitting so long. Battery could also be bad as in it has volts but not enough amps to properly maintain operating requirements. Good luck