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  1. #1
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    Furnace & AC Thermostat have no power or temp readout

    I've got a 2017 397TH, I had a power surge to the RV now the living room thermostat has lost power which controls the middle AC & furnace. Fuses in breaker panel are good, breakers are all good, there is 12V to the furnace fuse. All 12V breakers in battery compartment are good, everything else in the coach works. I've checked every accessible fuse in the RV, the only thing that hasn't been checked is the AC and furnace. I've requested help from GD but haven't gotten any response.

    Has this happened to anyone else? Where else should I be looking for the bad part?

  2. #2
    Commercial Member huntr70's Avatar
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    The control board in the a/c is probably toast.
    Steve- Inventory Manager at Tom Schaeffer's RV, Shoemakersville, PA www.tomschaeffers.com
    [email protected]
    2011 RAM 3500 SRW Outdoorsman Edition 4X4, 6.7 Cummins--TWEAKED!
    2021 Reflection 310RLS

  3. #3
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    Quote Originally Posted by huntr70 View Post
    The control board in the a/c is probably toast.
    I replaced the control board in the a/c and still the same problem. I swapped out thermostats with know good one still the same thing no power to the thermostat.

    Any other ideas?

  4. #4
    Seasoned Camper phonemannn's Avatar
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    Quote Originally Posted by BBest59 View Post
    I replaced the control board in the a/c and still the same problem. I swapped out thermostats with know good one still the same thing no power to the thermostat.

    Any other ideas?
    Wiring to the thermostat.
    2017 F350 Lariat, Dual rear wheels
    2017 GD 311BHS

  5. #5
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    The wiring looked from the ac and looked good at the thermostat.

  6. #6
    Long Hauler offtohavasu's Avatar
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    The issue may be in between. Looking good and being good are two different things. You'll have to ohm out the wires from point to point to see if they're good.
    Curtis, Christine, Cole, and Charlotte

    2007 Chevrolet Silverado Duramax LBZ, CCLB
    2020 Momentum 351M

  7. #7
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    Now I may not be correct on this, but power to the thermostat comes from the furnace, so check for 12V there. I vaguely remember a fuse at the furnace on this line. I also believe the wiring is color coded from the thermostat to the furnace but I don know which is the power.

    Hope this helps
    Keith

    Please correct me if I am wrong
    2018 Reflection 150 Series 220RK 5th wheel with 6K axle upgrade. B&W 25K OEM Companion, Steadyfast system, 2022 F350 SRW 6.7 King Ranch 8' bed, Trailer reverse lights, rear spare tire holder, storage tube, sumo springs, Victron MultiPlus 12/120/3000, and Solar

  8. #8
    Big Traveler
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    I'd look behind the furnace for an inline fuse and check the board on each end for 12 volt (furnace and air) for juice.
    2019 Momentum 395
    2018 Ram 3500 DRW 4.10 AISIN

  9. #9
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    I have a 2018 350M and have this exact problem. Did you find a solution? Where is there a fuse on the furnace?

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