Nothing wrong with the alternator. Delco alternators won't work with a standard diode isolator, they need +12 volts on the B+ post to initialize the regulator chip. Either install a diode...
Hook up only the sense wire to the S post, nothing to the I or R posts, in addition to the big ground and the B+ output cable.
This will get you going until you get the Sterling.Delco compatible isolator
The "I" post is for indicator lamp. Connecting excite to this will permanently damage the alternator.
I only work on old stuff and only for my pleasure, but Delco used to use the "generator" light to provide the exciter voltage to the alternator. Bad light bulb means no alternator output....
You're right I think the old Delcos (before Sense technology) worked this way, the new Delcos have output with nothing connected to the "I" post.
Maybe the 2 small wires at the isolator go to a battery maintainer for the chassis battery, like a battery tender or heart echo charger.
Guess I missed that memo.
Upon starting the coach, I went to high idle (1000 RPM) and saw low volts at the gauge. Then I measured voltage at the center terminal of the isolator. 1.7V. Measured the voltage at the pos...