Before attempting any repairs or testing, check out the gas safety and electrical safety pages.

The Dometic manual switch (shown below) is used in almost every Dometic manual refrigerator built after 1980. It's mechanically simple. Terminals opposite each other can be connected at various times depending on the turning of the shaft. Only terminals opposite each other can be connected. The back end of the shaft running through the switch is often attached to a gas valve to turn it of and on. There are different variations of this switch. There are different shaft lengths; and some have more terminals.

On the bottom side of the switch (not shown), there is a set of points between each set of opposing terminals. A cam on the switch shaft pushes various sets of points close, or allows them to spring open, depending on the shaft position. The selector knob at the front of the refrigerator turns the shaft.

Troubleshooting
Sometimes dust gets on the points, especially if the switch hasn't been used in a while. If you suspect a switch problem, often times rotating the switch back and forth three or four times will "clean" the points and solve the problem. If that doesn't work, the switch has to be accessed for further troubleshooting. Using a volt meter, test for proper voltage at the input and output terminals of the switch. For example, if the Elec position is selected on the knob, there should be 120 volt at the input terminals and the output terminals (directly across from the input terminals). The screw terminals are the 120 volt AC input terminals. Normally, if the switch fails, it should be replaced. However, cleaning the points may solve a lot of problems.