Truck Forums - 1995 Silverado, Intermittent Power Delivery

Hi everyone,

I've got a 1995 Silverado, half cab, 5.7L; don't think that's super important, but including it.

I got stuck at an Autozone because I went to start the truck; turned key to ACCESORY, got power, cranked it and nothing. no sound. not even a click from the starter. Checked battery cables, and by just fiddling with them, I was able to get the power to everything when switching to ACCESSORY again, but as soon as I tried cranking, it died.
Took him in since I had to get the AC and exhaust redone anyway, and the mechanic said terminals on the battery were stripped causing a horrible connection; gave me a new battery, terminals, and wires.

Now here's where my problem is...
Everything has been great and I thought the problem was fixed, but I went out to start him again, and turning to ACCESSORY, I got power (radio's going - doors locking - windows working) go to crank and boom. Just dies.
Fiddle around with the battery cables, and bam, can start the truck.

What would be causing this intermittent power delivery?
I don't have access to a good electrical diagram and I know how to troubleshoot circuits so I'm thinking maybe I can tackle this problem if I just know where to look (and if it's accessible).

Any ideas?
Much obliged,

- Chris