So I dug into mine today and the problem was a torn trigger wire at the base of the gun cable. This is from the cable twisting in its socket. So here’s the setup:
The trigger in the handle is just a shell. There’s a small switch in side the handle with (in my case) two blue wires soldered to it.
I went to the base of the gun cable and removed the rubber boot. As I was removing it, I saw a broken wire. I then cut through the electrical tape to find the rest of the wire. So it looks like those blue wires run the length of the gun cable and are then soldered onto other wires that lead to the 4-pin plug. The junction of the plug wire and the switch wire failed due to me not having the gun cable secured tightly enough, allowing it to rotate and stretch the plug wires, forcing a break. A quick solder job set it right. I taped the wires back down, reinstalled the rubber boot, and it tested fine.
I plan on feeding the wire back through it tomorrow and seeing if I can’t finish up my current weld job.