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...
AS Chris told you, the Compressor relay is fused closed. The Compressor is coming ON and because NO FAN is running, the compressor is overloading and the Overload switch kicks it out. When it cools down, it comes back on. You need a new upper control board. The compressor relay is not a separate part. Doug