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diamonddogdogs's avatar
Aug 12, 2017

a/c

We have a 2008 Phaeton, diesel. A/C will not come on. Had new thermostat installed, tried today and a/c will still not come on. (Of course it works at the dealership). What am I missing??? Have tried with shore power and generator. Checked circut breakers, they are all on.
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    Ok since you have a THermostat there are TWO power sources needed for the A/C to C the A.

    12 volt and 120 volt

    SOME A/C's are "Chatty" (Have led indicator lights on the control unit, you may be able to see through the filter) some are not.. I have one of each.

    Now. the 12 volt system consists of the thermostat and a relay (And of course your 12 volt source) possibly multiple relays.. IF there is no 12 Volt. or if trhere is a loose wire.. You get what you get.

    My personal "Sometimes it works" issue was the 120 volt and as a result of how I fixed it (Read on) I came up this joke: Many RVers have a few screws loose.

    Now, you may have guessed (from what came before) I am talking about the kind of screws you tighten up with, in this case a #2 Square bit and if you did GOOD.

    I started my Tribble shoot by removing the face plate from the breaker panel.. I then noticed wires were LOOSE ENOUGH that they could move in the clamps on the breakers (THIS IS NOT NORMAL!!!!) So I killed the mains and applied the aforementioned #2 Square.

    one breaker took 3.5 Turns to tighten.

    NOTE: UNPLUG first (Kill the mains) but that's where I'd start

    Next all other 120 volt connections, along the way Includign the ones at the A/C itself.
  • diamonddogdogs wrote:
    yes, there is 12 volt power.

    Battery disconnect is on. Ceiling lights work.


    Does the Wall tstat display come ON?. Have you checked the 120 breakers in the rear? DO NOT just look at them turn them all off and turn them back ON. Do you have Microwave display(Inverter OFF!)?
    Do the TV's work? If you plug into a 120 outlet with a fan or hairdryer, does it work? Does the Inverter remote panel show charging? Doug

    PS, ALL the ceiling lights work? The front 2 ceiling lights above the drivers and pass seat are connected to the chassis battery.

    DID you have at the Dealer for this exact problem? Did it work for you at the Dealership after they fixed it? WHY was the wall tstat replaced?
  • Have you turned the Coach battery disconnect ON? Do you have interior ceiling lights? If you do, your battery disconnect is ON. If NOT, that is your problem. Doug

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