[DETAILED] STEP BY STEP INSTRUCTIONS

Pull the air conditioner out of the window

1. Remove the screws that hold the accordion filler panels in the window frame.

2. Push the accordion filler panels inward to clear the window frame.

3. With someone’s help, support the air conditioner and raise the window sash.

4. Carefully lift the air conditioner out of the window and set it on a stable work surface.

Remove the front grille panel and filter

1. Grasp the sides of the front grille panel at the top and pull the front grille panel out and off of the air conditioner.

2. Pull out the filter. Remove the control panel

3. Remove the screws from the sides and bottom of the control panel.

4. Pull the control panel up and hold it above the air conditioner while you unplug the wire harness connection for the user interface control board.

Set the control panel aside. Remove the front panel

1. Remove the screws from the sides of the front panel.

2. Pull the front panel off of the air conditioner and set it aside.

Remove the outer case

1. Remove the screws from the exterior of the outer case.

2. Remove the center stop for the accordion filler panels. Remove the hidden screw that’s under the center stop.

3. Pull outward on the bottom of the outer case and remove the outer case from the air conditioner.

Remove the electronic control board

1. Remove the screws from the electronic control board case. Pull the cover of the electronic control board case out to expose the electronic control board.

2. Take a digital photograph or otherwise document the location and routing of wires connected to the electronic control board so you can connect the new one correctly.

3. Pull all wires off of the electronic control board.

4. Remove the mounting screws that hold the electronic control board in the case and pull out the electronic control board.

Install the new electronic control board

1. Position the electronic control board in the case and reinstall the mounting screws.

2. Using your photograph or other documentation as a guide, connect all the wires to the new electronic control board. Make sure that wires are properly routed so that they’re not pinched or damaged during reassembly.

3. Position the cover of the electronic control board case and reinstall the screws.

Tip: Make sure that wires aren’t pinched when reinstalling the electronic control board cover.

Reinstall the outer case and front panel

1. Position the outer case on the air conditioner and reinstall the screws, including the hidden screw in the center.

2. Position the front panel on the air conditioner and reinstall the mounting screws on the sides of the front panel..

Reinstall the control panel

1. Position the control panel above the air conditioner and plug the user interface control wire harness back in.

2. Position the control panel on the front of the air conditioner and reinstall the mounting screws in the control panel.

Reinstall the front grille panel and filter

1. Insert the filter on the front of the air conditioner.

2. Position the front grille panel on the front of the air conditioner and snap the panel into place..

Restore the power

1. Plug the air conditioner into the electrical outlet.

Replace the window air conditioner evaporator thermistor

The evaporator thermistor is a temperature sensor that is mounted on the evaporator. It monitors the temperature of the evaporator to detect excessive frost on the evaporator.

The thermistor communicates that temperature to the electronic control board through a wire harness connection. If the evaporator frosts up, the electronic control board will detect the frost according to the temperature communicated through the thermistor.

If the thermistor is defective, the electronic control will not properly detect and eliminate the frost. Replace the evaporator thermistor if it doesn't properly detect the evaporator temperature.

Replace the window air conditioner electronic control board

The electronic control board regulates the compressor, evaporator fan and condenser fan in the window air conditioner. If the electronic control board doesn't activate those components properly, replace the control board. When a window air conditioner won't cool or won't start at all, the electronic control board might be the problem. This step-by-step repair guide shows how to replace a window air conditioner electronic control board.