So I recently inherited a 1989 e-350 class C. 460 EFI. Battery wasn't charging so I threw on a new alternator. No power still.Looked through the forums and saw a number of threads on the subject. Looked at the wiring diagrams etc. Using volt meter I checked for power at the black wires and got power with key off. I also have power on the two wire plug with engine in run position. I noticed some of the 2g alts have three wire plugs. Mine is a two wire but the Alt is a fresh reman. Some of the diagrams indicate I need three wires with the 3rd running to the white alternator wire? I'm at my wits end at this point. Electrical is barely in my wheelhouse at all.

 

You should not repair that alternator to workiung conditions. lest you burn your motorhome down

Get a ford 3g or a GM CS/AD series alternator