Originally Posted by 74Argosy24MH
Check it with an ohm meter back to the small red wire in the plug on the alternator. If it is the same wire, it needs to either be tied in with the black/brown wire in the plug or to a terminal that is hot when the ignition switch is in the ignition position.
There are three wires coming out of the alternator plug. One goes to the ignition, the brown wire is just hanging loose and is taped up. I believe this is for a dash charge light. The third wire is a red 16 gage one that may very well be the mystery wire. I have checked Airstream, several dealers, Chevrolet, Workhorse, and GM and nobody can tell me what this wire is supposed to do.