Why does one roof ac shut off when I turn on the engine key?

[Atropine]

Hi everyone-
I recently bought a 99 Gulf Stream 34' SunSport with cummins ISB. Thx to your help I discovered my generator was capable of running both roof ac units at the same time. I believe the gen is a generac 6600 lp genset. It has 2-30amp breakers. Both roof ac's run simultaneous (after about a 1-2 min delay at startup.) on gen power with the coach engine off and ignition key in off position. But when i turn the ignition key to the on position (or start up the diesel engine), the front roof ac stops working completely. It does not re-cycle back on until i turn the ignition key off. Does this seem right? The rear ac keeps working at all times, no worries there! Any ideas? I need to be able to run both roof ac's while driving down the road...

[ga traveler]

It sounds like a relay is shutting off the 12 volt to the front AC. Call Gulfstream and check with them. Our dealership was a Gulfstream dealership and this is not normal.