Have a 2003 36' Gulfstream Ultra Supreme. Never had issues with A/C's b4 & don't know anything about them? I do have an issue with the front unit now.Unit works as intended when controlled by thermost...
I would verify that the power to the rig is correct. Test the system to insure the neutral is in good shape. One of the small three light tester may aid in this test. best way is to use a volt meter. test at the 120/240 volt distribution panel. First item that could be issue is the neutral relay in the transfer sitch.