k0ua
Epic Contributor
I still don't see how disconnecting the batt isolates the PCM from the welding voltage??? It disconnects it from the batteries 12v, but the PCM still has wires hooked to the chassis and various other sensors that may be conducting the welding voltage
I have always though the same thing, not to mention those sensors are connected by wires, and those wires lay next to the chassis that could have current flowing thru it. (if you are dumb enough not to put the clamp as close to the weldment as possible) and if there is current flowing in the chassis and a copper conductor is nearby, a voltage can be induced into the conductor by induction. And Mosfets and other semiconductor devices sleeping quietly in their beds could possibly be damaged. I am of the OK, a powered down semiconductor is probably less susceptible to damage than a powered up one, and disconnecting the battery terminals sure can't hurt, but I am not so sure it is the panacea that some have alluded to. So I think disconnect the battery, both leads, and make sure they do not touch the chassis, and put the "ground" clamp as close as possible to the weldment, to minimize current flow in the chassis of the vehicle, and hope for the best. I sure don't claim to be an expert in this, but those are my thoughts.
James K0UA