75 chevy wiring issue

[scotty17509]

So i finally got my truck back together after installing a new exhaust, an MSD ignition and new intake. Anyway while running the msd wires into the cab i accidently ran a screw through the power wire for the msd box. So not knowing, i hooked the cable to the battery. Now the heater fan does not come on and the gas tank switch doesnt switch tanks. I checked all the fuses i could find and obviously fixed the wire but cant get it working. Does anybody know which wire i may have burnt out or what i should check?