Before working with electricity, visit the electrical safety page.
AC (120 volt) is the first choice of the circuit board for heating the cooling unit. The 120 volt input goes directly to the circuit board (passing through a junction block). If the circuit board senses 120 volt and the thermostat is calling for cooling, the circuit board sends 120 volt to the electric heat element via a relay built onto the circuit board.
Troubleshooting AC Operation
At this point, the problem could be in the AC circuitry, the thermostat, or switch mechanism. A quick test for the thermostat and switch would be to unplug the AC cord and see if the refrigerator tries to light on propane. If it does, the thermostat and switch are all right. If it doesn't, check out the electric thermostat and switch page. If these two components are good, check out the circuit board for possible problems.
After determining that the thermostat and switch are good, the next step is to see if the problem lies in the heat element itself, or in the lack of voltage to the element. The heat element on the RM1303 vintage models connects to a plug wired from the circuit board. Later models have the element connected directly to the circuit board. Locate this connection and disconnect it if necessary to check it for 120 volt to the element. Since you're working with live voltage, be careful not to harm yourself or the equipment. Disconnect the power if necessary, until you're in a safe position to test. If power is present at this point and the element didn't get hot, the heat element is bad. If voltage is not present the circuit board (or connections between the circuit board and heat element ) is bad. We already know there is 120 volt to the circuit board, since when we unplugged the refrigerator earlier, it tried to light on gas. If it is determined that the circuit board is bad, the heat element may have been the cause. See the circuit board page for more details.
RV Mobile Inc. 11715 HWY 99, Everett, WA 98204
The owner of RV Mobile Inc. apparently suffered a heart attack and the original website was shut down.
It has been reposted here to preserve this wealth of information RV refridgerator information.