• Chris
    2
    Hi All,

    I watched Ray's video of replacing the stock thermostat with a programmable one and thought I could do it too. Well, I was wrong...and it isn't quite working.

    The wiring on the original thermostat, the high fan was blue and the low fan was brown wires. I don't have a pic of the orig thermostat before I pulled those two wires, but you can see where they came from. Those two where the ones I wired to the toggle switch. No go. I am pretty sure the issue has to do with the ground wire. There is no where for the ground in the new thermostat (I got the same model as Ray). When I rewired the old thermostat, nothing worked until I wired the green wire to ground. I am sure that I am missing something!

    Any help would be greatly appreciated!!

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  • Ray
    672

    Your thermostat appears to be a Dometic, not a Coleman Mach like I have, so it likely is a little different in the wiring.
    I found this article on ModMyRV and it appears to look like the same thermostat as yours.
  • Chris
    2
    Ray, that is awesome!!! Yes it is a Duo-Therm by Dometic. I should have included that. That certainly answers the big question!! I really don't understand it, but it seems the green wire is the hot one! Not sure why it was plugged into the GRD on the original thermostat. :chin:

    Starting over, I unwired everything and just tried the green wire with each of the others. The white wire started the heater as expected. The yellow wire (ac) did nothing...strange. Shouldn't this start the AC?

    I didn't put the green to the red...I feared fire or something...

    Afterwards, I thought that I would go way back and just reinstall the orig thermostat, to make sure that I didn't ruin anything. Everything seems to work fine including the low and high fan. I cannot test the AC because it is too cold in my shop for it to kick on.

    Anyway...I am stumped. I'd greatly appreciate any other thoughts/suggestions.

    Thanks again for the link!!!
    Chris
  • Chris
    2
    Oh, forgot to mention that the I checked the AC breaker and it looks good. Also, I am on shore power.
  • Ray
    672


    I think this video may be the one to help, looks just like what you have
  • Chris
    2
    Thanks Ray! This confirms the info from your first link. I feel more confident redoing the new thermostat install!!!

    I am still a little concerned that the AC didn't start when I connected the green and yellow wires though. Is there possibly another fuse to check other than the breaker? Or am I wrong in thinking that the compressor would start up immediately if I connected the wires?

    Thanks again!!
  • Ray
    672
    I think you need to apply power to both the AC and a fan speed wire at the same time.
  • Chris
    2
    Thanks Ray!! I think you know everything!!! :up:
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