Good day, If your talking about the defrost thermostat, it should look something like this.
In the freezer compartment, remove the rear panel. You should be looking at the cooling coil. The thermostat is clipped to the top of the coil, usually on the right side. The heater is mounted to the same coil but is mounted to the bottom of the same coil. To check the heater you will need an ohm meter. It should read no more than 30 ohms and appear in good condition. Testing the thermostat is a little different in that it must be tested while still cold. It should test out at zero ohms (no resistance).
If both check good the last item is the timer which is located in the fresh food compartment on the top. There is a hole where you can insert a screw driver to advance it. It will only turn clockwise. With the machine running, turn it until the machine shuts off. Leave it like that. If the machine turns itself back on within 35 minutes, the timer is O.K. If not, the timer is bad, and must be replaced. All 3 items can cause the machine to allow the cooling coil to frost badly enough to deny the fresh food compartment any supply of air. Also, the fan motor in the freezer section, if not running can cause the same problem. Here's a good tutorial on defrost systems.
Answers & Comments
Good day,
If your talking about the defrost thermostat, it should look something like this.
In the freezer compartment, remove the rear panel. You should be looking at the cooling coil.
The thermostat is clipped to the top of the coil, usually on the right side.
The heater is mounted to the same coil but is mounted to the bottom of the same coil. To check the heater you will need an ohm meter. It should read no more than 30 ohms and appear in good condition.
Testing the thermostat is a little different in that it must be tested while still cold. It should test out at zero ohms (no resistance).
If both check good the last item is the timer which is located in the fresh food compartment on the top. There is a hole where you can insert a screw driver to advance it. It will only turn clockwise.
With the machine running, turn it until the machine shuts off. Leave it like that. If the machine turns itself back on within 35 minutes, the timer is O.K. If not, the timer is bad, and must be replaced. All 3 items can cause the machine to allow the cooling coil to frost badly enough to deny the fresh food compartment any supply of air.
Also, the fan motor in the freezer section, if not running can cause the same problem.
Here's a good tutorial on defrost systems.
http://www.appliance411.com/faq/howdefrostworks.shtml