Question about Dometic Rooftop RV Air Conditioner

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No 12 volt power to duo therm comfort control box

I recently replaced a start capacitor on our front 15,000 BTU A/C unit. Now I do not have any 12 VDC power to the control board nor the comfort control box inside.

Checked both 3 amp fuses both inside and on the A/C's control board. Fuses are fine.

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  • bayouimage Aug 03, 2009

    Are you talking about the converter?

    The AC power feeding the camper is fine, both l20 volt A/C legs. I went to the 12 volt power distribution panel and checked 12 volt power leaving and going up to the A/C unit. There is 13.9 VDC passing thru the fuse and the fuse is good. The 3 amp fuse in the A/C unit on the A/C control module is also good. There appears to be a wiring break somewhere between the fuse panel and the front A/C unit.

  • bayouimage Aug 09, 2009

    I contacted Doubletree RV and talked to technical support. They were very helpful. I found a blown 3 amp fuse on the rear A/C circuit board and replaced. Both A/C units are now working fine. It seems as the 12 VDC goes to the rear unit first and then to the front.



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Check if you have 240V and then 12V to the secondary of the transformer if none then its your transformer that is faulty

Posted on Aug 02, 2009

  • relaga58
    relaga58 Aug 04, 2009

    there must be an open circuit w/c you can trace out with ohmmeter, it could be loose terminal or connector.

  • davikconsult
    davikconsult Jan 10, 2013

    What i have is a CCC control board up on top at the A/C unit. If it's the transformer, wouldn't that prvent the A/C unit from coming on too?



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