Dometic RM660 No 120V

[riverratmike]

I have a 1971 Prowler 24ft travel trailer that has a Dometic RM660 in it. Has worked great for a long time. Replaced heater element in it a couple of years ago. Electric operation quit on me a few weeks ago while out on a camping trip. Got out my multimeter this afternoon to start checking things. There is no 120V at the junction block that connects the heater element wires. I have power to the plug. This thing is old but works great when it works and I'm going to try my best to fix it and avoid buying a replacement. The RM660 works great on LP but like to have electric working on it also. If anyone might let me know on things to check I'd appreciate it very much. Thanks.

Mike

[idroba]

Those old Dometic's used a pretty simple system for the 120 volt side. The power comes in, goes through a thermostat which only serves the 120 volt system (a second one is used for the gas side) and then through a toggle switch which is activated when the knob is turned from gas to electric. A mechanical lever turns the gas valve to off, and that pushes a knob on the valve to turn the electric on. You can see how it works pretty easily from the back access port for the refrigerator.

I would look to see that the mechanical arrangement to lock the electric off when the gas is on and vice versa is working, confirm power at that switch too. If all that is good, the only other part is the 120 volt thermostat.

[riverratmike]

Originally Posted by idroba

Those old Dometic's used a pretty simple system for the 120 volt side. The power comes in, goes through a thermostat which only serves the 120 volt system (a second one is used for the gas side) and then through a toggle switch which is activated when the knob is turned from gas to electric. A mechanical lever turns the gas valve to off, and that pushes a knob on the valve to turn the electric on. You can see how it works pretty easily from the back access port for the refrigerator.

I would look to see that the mechanical arrangement to lock the electric off when the gas is on and vice versa is working, confirm power at that switch too. If all that is good, the only other part is the 120 volt thermostat.

Thanks for the reply. My only problem I'm having now is getting access to the wires underneath the unit and testing them. There's really no way of doing that unless I remove the whole thing from the trailer. I might just give up on the electric part of it and just use the LP.

[idroba]

Yes, unfortunately that is true on many of the Dometic's. As I want the propane to run while on the road, and usually boondock camp, propane is much more important to me than 120 volt operation, and I usually just start and run my refrigerator on Propane all the time.

[riverratmike]

well I tried something. I sprayed all the workings under the fridge with WD-40, let that sit over night and magic happened. Came out the next morning with my volt meter and boom. There was 120V going to the heating element and continued to work normally. Must have been some corrosion in there somewhere or a loose connection. My 120V works just as well as my propane and would much rather use the 120V than the propane.