Hey guys, thanks for having me. First time on this forum and I have spent some time searching for a member with a similar question--no luck. I just picked up a 59 f100 swb 292. The charging system seems weak so I yanked the alternator. I found it has a delco 7127 internally regulated unit but the regulator pigtail had not been in use. Why would this be? And more importantly is it effective w/o it? Thanks, James.

 

Even the alternators that are one wire self exciter have the two prongs. However, I believe it would have to be a Delco 7127SE to be a self exciter.
Since you have it out, take that one into a place like Advance Auto and have them test it for free.

I know that the Delco 10si and 12si units are one wire only and extremely common. The 10si is a 63 amp and is cheap, $40 or so at the parts outlets. That may be the easiest solution.

HTH

 

The alternator, most likely...has been swapped in.

1957/64: Generators were standard equipment, alternators were optional. The only alternator available on 1957/60 trucks: Leece-Neville.

Delco alternator installed on GM vehicles, has been owned by GM since circa 1915.

 

I highly recommend a 1996 140A Camaro Alternator. Easy install, work perfect with original charge indicator lamp.

 

If it was me, I'd pitch that pos gm alternator and install a Ford 3G. It's a far superior alternator, easier to service and a Ford part. It does require 2 wires though.