Hey all- got a replacement handle for the welder. Original handle has a single trigger wire, replacement handle has two trigger wires. Anyone know how to wire it up? Thanks...
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The original gun must use a shield on the hose as the other conductor. Open the welder and check where the wire feeds into the hose. There must be another electrical connection there.

It's also possible your welder uses the main conductor as half the circuit. Hard to say. My Miller uses a 2 wire switch because I can change the polarity of the weld. A single wire switch may not work if you change the polarity of the welder.

Do you have instructions for your welder?

Generally replacement guns are spec'ed with the correct 'back end' for your welder

Toolguy, if you mean the guns with the sockets on the back end, this welder is perhaps too old for that. It's all hardwired in, so to speak.

Mike, there's a circuit diagram on the inside cover that in no way corresponds to the electrics inside. :-( I think it must be wired per your second suggestion, there is no electrical conn at the wired feed- the sleeve is nylon and it's clamped in a nylon block, no conductors in the area. I was hoping it was a simple open/close switch, but if it's for polarity changes, there must be something more going on. I'll look up the wiring for the handle, sounds like the trial/error method would be bad.

Cracked open the original handle- the switch has the one incoming wire- when you depress the trigger, it contacts the barrel of the gun. So I am going to wire the replacement trigger by splicing one wire in to the original trigger wire (which goes to the speed control switch) and the other trigger wire to the electrode wire coming out of the gun.

Sound good?