95 sonoma sls old vortec 4.3L won't start. ground at firewall melted.

[FlyingSolo28]

   I have a 95 sonoma sls 4x4 with the old 4.3L vortec. I noticed it was getting harder and harder to start. one day it wouldn't start at all. The fuel pump relay stuck on and flooded the engine full of gas. I replaced the relay, drained the gas out by removing the plugs, drained the oil and replaced with new oil and filter, new spark plugs all required length and gap, wires, ignition coil, battery, starter, positive cable, negative cable, MAP sensor, TPS sensor, IAT sensor. All those have been replaced. connections at starter and the rest of the positive and negative cables are routed correctly , clean surfaces, and tight. Starter still acts like its not getting enough power and everything dies out within seconds of holding the key in start position. Then smoke comes out of a ground wire at the firewall on the passanger side near the group of relays. It's runs along with the Low Pressure Cutoff Switch for the A/C Accumulator. 

   My question is this: Where does the wire lead? What circuit is it associated with? Would it cause the issue I'm having? Short to ground, but no fuses are blowing? Just a bad ground? Anyone encounter this before? 

   Please help!! I hate electrical gremlins!!