Dometic Thermostat Error Code 7

[BogeyPro]

Hello. I recently had a lithium battery upgrade. I am now on my first road trip, now in Eastern Washington and it is HOT as blazes🔥. When I turn on the Dometic thermostat to turn on the air conditioners. I get "Error Code 7", and they won't turn on.

I googled this error code and the recommended fix is to disconnect, shut down all power. Then check all the fuses, for both the 50 amp and the two 20 amp fuses for both AC's.

Confirming that yes, I am hooked up to 50 AMP power.

Confirming also that I also did the System Reset/Error Code.

Any ideas or suggestions most welcomed..

[GMFL]

E7 error code means loss of 120V power. Do you have a surge protector? If so it may be disconnecting power does to a camp ground power issue.

[wulfraat]

You mention a lithium upgrade… did you install an inverter/charger like a Victron multiplus? If you are using this type of unit to power your coach it must be on either in pass-through mode or assist mode for 120v to be supplied to the panel and your AIr Con.

Just another thought.

[BogeyPro]

Thanks for all of your help, it looks like it was the campground power supply after all. I moved to another campsite, plugged in the surge protector, and the two AC units fired up. All is well, things are much cooler now.