Checking, removing, cleaning, and reinstalling the ground straps is always a good place to start with all things electric on our rigs. Might want to add some dielectric grease while they are apart. At least you’ll know your grounds are good for this problem solving and for the future.
In THEORY, the generator should have nothing connected to the “chassis electrical system”.
It does send 120v power to the converter that powers your “coach” 12v
system. Correct me if I’m wrong fellas. Never heard of this particular situation before with a Classic.
Since you didn’t mention anything about which motor you have, I’m assuming you have the 454 gas powered and not the Isuzu diesel.
There have been discussions on whether the generator sends a charge to the chassis battery or not. I’m not exactly sure if it does or not. If it does, then you may have something as simple as a bad chassis battery. When the generator is running it may be supplying enough charge to the battery to keep it running….but once again, that would be assuming that the generator does indeed send a charge to the chassis battery. If you had the dash ac running, along with the fan on high and other various 12v
electrical demands of the 454, then maybe the alternator wasn’t keeping up.
Total guess. But like I said, never heard of this particular problem on one of our Classics.
WTH, check you chassis battery under load. Another thing to eliminate as part of the problem.