Dometic A/C won't turn on with remote or from unit

I have a Domestic A/C in my trailer. It has a remote that I have always used to control the unit. It also has two buttons on the overhead unit itself (cool and heat). I noticed that the AC wasn't cooling to the desired temperature. Think the fan was the only thing running. I can't get the unit to respond to the remote nor can I get it to respond by using the cool button on the unit itself. I turned the breaker off then back on hoping it was like a computer and shutting it down and bringing it up might help. But when I flipped the breaker back on the fan was still running but no response from the remote or either button on the unit. I then pulled the (phone jack) like cord out of the side of the over head control unit and the fan went off. When I plugged it back in, I can't get the unit to turn back on with either the remote or the controls from the overhead unit. Any suggestions?

Re: Domestic A/C won't turn on with remote or from unit

Kellyboy,

I'm thinking the phone jack-like cord might have a thermostat at the other end. Have you checked to see if maybe someone changed the settings? Also, if there is a thermostat, you need 12V DC for the thermostat to send signals to the A/C unit. If your battery is discharged, it would interfere with normal operation.

Re: Domestic A/C won't turn on with remote or from unit

Kelly, a few things ;

1). How many hours has this unit run and how old is it ?

2). What type of T-Stat do you have, digital or analog ?

3). If digital, are you getting any error codes on the T-Stat and is it lit (analog or digital
the light on verifies 12 VDC is present) ? see below

4). Have you tried cycling the power on/off again ?

5). The cable you unplugged is a RJ-11-6P-4C modular connector. It is the same modular
phone jack used in most houses. T- Stats do not like their cable pulled, jumped or
shorted while energized, bad things SOMETIMES happen.

6). It sounds like your compressor is not kicking in, this could be from several things.

7). Have you dropped the plastic trim inside to see if any plugs are apart ?

8). What is the line voltage coming in, are you in a brown out ? Dometic compressors won't
start if the voltage is below 108 ACV. Try it after dark or plug a digital volt meter (plug
in type) into a duplex outlet nearest your AC unit.

9). Look in your manual or Google your unit to look up "Trouble Shooting" your unit.


DOMETIC AC ERROR CODE - VULCAN to ENGLISH 8/12

1. Error Code:
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o E1 Loss of communication between the CCC 2 thermostat and all system power module boards. System will shut down.
o E1 Loss of communication between the CCC 2 thermostat and an individual system power module board. The LED will display error code EI and the zone number that lost communication. Any additional zones that loose communication will blink in addition to the current zone.
o E2 Open circuit or out-of-range indoor temperature sensor. All heat , cool, and dehumidify operations will be locked out. Manual fan operation will continue.
o E3 Shorted Indoor Temperature Sensor. All heat, cool, and dehumidify operation will be locked out. Manual fan operation will continue.
o E4 Open circuit or out of range Outdoor Temperature Sensor (select models). Heat pump and dehumidification operation will be locked out. Air conditioner, furnace, heat strip and fan operation can continue to operate.
o E5 Open circuit or out of range Freeze Sensor. Air conditioner and dehumidification operation will be locked out. Heat pump, furnace, heat strip and fan operation can continue to operate but displays the last temperature set-point.
o E6 Open circuit Humidity Sensor (Select Models). Air conditioner and dehumidification will be locked out. Heat pump, furnace heat strip and fan can continue to operate.
o E7 Loss of 120 VAC power to all power module boards on the system. The system will shut down.
o E8 Invalid zone configuration. The heat pump and heat strip DIP switches are both set to the ON position in one zone. Heat pump, heat strip, air conditioner, and dehumidify operation will be locked out in the affected zone.
o E9 Invalid zone configuration. The dehumidifier DIP switch and either the heat pump or heat strip DIP switches are set to the ON position in one zone. Heat pump, heat strip, air conditioner, and dehumidify operation will be locked out in the affected zone.
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Re: Domestic A/C won't turn on with remote or from unit

Is the fan set to auto on the remote??

Re: Domestic A/C won't turn on with remote or from unit

Check the fuse in the 12 volt panel. The thermostat control is 12 volt.