[Archived]

The industrial switch in the overhead controls a relay that allows 120v ac power to the air conditioner unit. Relay failure is not uncommon, and may likely be your case. Following all appropriate electrical safety precautions to prevent injury due to electric shock, I would check the relay coil and ensure there is 12vdc control power to the coil, ruling out a dc control circuit problem, then verify 120v ac to the input side of the relay, and out when energized. I suspect the relay contacts are probably burnt up.

[Alvie]

Thanks for the reply. I don’t know where to find the “industrial switch in the overhead”?

[Dick]

Eric, I have a 98 CC and my coach does not ues the square lighted Sun Mullion switches to interface with the roof airs. Do I understand yours is different.

My 3 roof units are wired to a breaker panel in the bedroom on 20 AMP breakers and I don’t know where the thermostat gets its power. I saw where you checked the breakers so like the previous reply check to see if the thermstat is calling for A/C check to see if you are getting 120 V at the unit. Pull down the grill that covers the air filter and you will find a junction box where the 110 V wiring comes in. At least mine is wired this way. Be cautious, hopefully the wires will be hot.

If you have power to the unit then go to the internet snd check Dometics website to see the drawings for your modle units to see if there is a reset swith or breaker in the unit itself. Assuming you have Dometic brand units.

My thermostat controlls the three roof units and nothing else.

Good Luck

[Archived]

Yes, that is correct. There are three thermostats, but I have three sunmulon switches in the front overhead that turns on each air conditioner. I will check all that has been suggested. Thanks,

Eric