How To Replace The Thermistor On A Refrigerator With Frozen Evaporator Coils
Posted on: 10 May 2016
A refrigerator's thermistor is a temperature sensor that helps ensure the interior temperatures facilitate the necessary cooling and defrosting. When a thermistor fails, the refrigerator can stop defrosting and the evaporator coils inside the freezer can freeze up. If your refrigerator has digital diagnostics, you can easily check to see if the thermistor is the problem. Otherwise, you can simply switch out the thermistor and see if the change solves the problem.
Things You Need:
- Socket wrench
- Wire cutters
- New thermistor
- Wire nuts
- Liquid silicone
Step 1: Remove the Old Thermistor
Unplug the refrigerator from the electrical outlet. Remove any shelves or drawers that block the rear panel of the freezer.
Lift off the light cover. Unscrew the lightbulb. Use a socket wrench to remove the mounting screws that hold the rear panel in place. Put the screws in your pocket so you don't lose these small pieces as you work.
Detach the grounding wire that straddles the rear panel's upper edge. Slide the panel up while pulling out to take the panel off its track. Pull the panel out of the freezer and set aside.
Unclip the thermistor from the evaporator tube. Use wire cutters the wires close to the old sensor bulb.
Step 2: Install the New Thermistor
Prepare the new thermistor for installation by trimming the wires a few inches from the bulb. Use the wire cutters to separate the two wires by clipping the wires apart at the opened end. Strip back the insulation on the wires so that a bit of wire is exposed; you can use the size of your wire nut as a gauge for how much wire to expose just make sure the exposed wire is at least slightly smaller than the nut.
Repeat the stripping on the wires inside the freezer where the old thermistor was located. Position the stripped wires on the thermistor next to the stripped wires in the freezer so that the like wires from each set are matched together.
Slip a wire nut over the end of each pair to connect the segments together. Apply a drop of silicone to the opening in the wire nut to finish sealing the connection. Slide the mounting clip onto the new sensor bulb and clip the bulb to the evaporator tube.
Step 3: Reassemble the Freezer and Test
Put the rear panel back into place by angling the panel down and inwards until the panel finds its track. Then simply push down to finish reinstalling the panel. Use the socket wrench to tighten the mounting screws to secure the panel.
Put the shelves and drawers back in the freezer. Plug the refrigerator back into the electricity. Allow the refrigerator to sit for a few hours then check to see if the coils are defrosting. If your unit is still experiencing issues, call in a refrigeration repair service (such as Appliance Doctor).
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