New owner of a Roadtrek 210, way too much isolator info!

[4csoncmpr]

If you put in a new alternator and it's not showing the correct voltage and you have an isolator, make sure the connections in the alternator harness and the excite wire/relay are all good!

I recently purchased a 2007 Roadtrek 210P from a private seller nearby.
Beautiful looking RT, did the test drive & all seemed well.
We didn't take the time to test everything but it all looked in great condition and what we did test seemed to work well.
So Saturday night before Columbus Day we finalized the transaction and drove the RT home.
24 hrs later, Sunday, we had to drive by the same area that we purchased the vehicle and wouldn't you know, the alternator failed and we stopped dead in our tracks in a parking lot a block away from the sellers home.
We had family close by so we weren't stranded and made the best of things.
Columbus day morning I picked up an alternator and engine battery and went to work. Didn't do the trick, alternator not charging.
Brought the RT to the sellers mechanic.
They could not find what the problem was. Tried another alternator.. no go!
They ended up sending my original alternator out to be rebuilt.
They also cleaned up the sense wiring to the alternator and bypassed the isolator so I could get the RT back home.
In addition, they found the house batteries dry so added water & charged them & also took out the crimp on alternator "excite" wire from the engine harness which was very loose and causing a relay on the isolator to click frequently.
Days later I found a youtube video from emarine that went over testing an isolator. I tested the isolator and the relay... tested fine.
So I put all the wiring back in place and ran a new wire to the fuse box for the alternator excite. I used a littlefuse add-a-circuit (which came with a bunch of fuses... nice!).
Working perfectly now! I think I still need to replace the house batteries at some point.
So, dead house batteries? Poor Alternator harness connections? Bad excite wire connection to harness? My guess is the real issue was the bad excite wire connection (GM based).