Have a Coleman Mach A/C and was having problems,whirring sound on start up no cooling. Caravan repairers wanted to replace the unit, at $1800.00 plus gst, plus labour.
Son in law's cousin is an accredited refrigeration and air conditioning mechanic. He found an issue with the fan and fixed it, found a leak, repaired it. Re gassed the system, tested and run the unit for several hours.
Old School tradesman who wont rip you off. Also does domestic stuff.