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How do I replace an Ambient Thermistor in a Window Air Conditioner?

The window air conditioner ambient thermistor-also known as a temperature sensor-senses the temperature of the air entering the air conditioner and sends it to the electronic control board, which cycles the compressor on and off to maintain the set room temperature. A wire harness is used to connect the ambient thermistor to the electronic control board. The electronic control board will not cycle the compressor on and off if the ambient thermistor is bad. If the ambient thermistor doesn't accurately measure the room temperature, replace it.

Follow these steps to fix your issue:

  1. Disconnect electrical power

    The wall outlet has a power cord.

  2. Pull the air conditioner out of the window

    The accordion filler panels are in the window frame. To clear the window frame, push the accordion filler panels inward. Support the air conditioner and raise the window sash with someone's help. Lift the air conditioner out of the window and put it on the work surface.

  3. Remove the front grille panel and filter

    Pull the front grille panel out of the air conditioner by grasping the sides of the panel at the top. The filter needs to be removed. If necessary, clean the air filter.

  4. Remove the control panel

    The control panel has screws on it. Hold the control panel above the air conditioner. The user interface control board has a wire harness connection. The control panel should be left alone.

  5. Remove the front panel

    The front panel has screws on the sides. Put the front panel of the air conditioner away.

  6. Remove the outer case

    The screws need to be removed from the exterior of the case. The center stop needs to be removed. There is a hidden screw under the center stop. Remove the outer case from the air conditioner by pulling it outward.

  7. Remove the ambient thermistor

    The electronic control board case has screws. To expose the electronic control board, pull out the cover of the electronic control board case. The control board has a black ambient thermistor wire. The mounting clip on the front of the evaporator needs to be removed.

  8. Install the new ambient thermistor

    The mounting clip has a new ambient thermistor in it. The ambient thermistor can be plugged into the T1 Connector on the electronic control board. Put the electronic control board case in place. Make sure the wires are not pinched when you change the electronic control board cover.

  9. Reinstall the outer case and front panel

    The outer case needs to be positioned on the air conditioner. The screws in the outer case have hidden screws in the center. Put the front panel on the air conditioner and put the mounting screws on the sides of it.

  10. Reinstall the control panel

    Plug the user interface control wire harness back in if you position the control panel above the air conditioner. The control panel should be positioned on the front of the air conditioner.

  11. Reinstall the front grille panel and filter

    The front of the air conditioner has a filter. Attach the grille panel to the air conditioning unit by snapping it into place.

  12. Restore the power

    Attach the air conditioner to the electrical outlet.

Time required:

45 minutes.

You would need the following tools:

phillips screwdriver, work gloves.

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