Rear A/C not working

[Bill Staley]

Good morning,  Our rear A/c is acting up.  It quit working.  We found a broken wire in the junction box in the ceiling where the unit is connected to the 110 source from the breaker.  Fixed that.  Now when the unit comes on it runs (I think fan only) for about 40 seconds and then shuts off.  It then never comes back on.  There is what appears to be a relay in the junction box that seems to be involved because it is connected to the unit wiring.  Any idea what the relay's function is?  We have 3 Dometic roof units.  The other 2 are working great.

I've reset the thermostat, and other "reset" type stuff.

[Mike Shumack]

What model do you have (i.e. 600xxx, 620xxx, 630xxx)?
I have a troubleshooting manual (but too large to attach here at 659KB). Here are two pages from the manual that might get you started - PM with your e-mail address if you want the whole manual.

Here is the reset procedure - but it sounds like you already did that.

It also sounds like you have communication from the 5-button thermostat to the AC unit since you can get the fan to run (I assume the LEDs on thermostat come on, meaning you have DC power to  it).

[Bryan Beamon]

Bill, do you have voltage power to the air conditioner once you fixed the broken wire? Those junction boxes join the wires with screw on wire caps combining solid copper with braided wire which sometimes can be misconnected. Just a thought.

[Paul Aronson]

In out 2007 the rear ac and washer "share" a single 20 amp breaker. There is a load shed device to allow only the washer or ac to aoperate at the same time. Possibly the relay you mention is a load shed circuit and is not wired correctly. My load shed box is an Intellitec unit and there is good info on their website on how it should operate.