Whirlpool window or portable air conditioner displays E1 and stops cooling or controls become unresponsive.

Safety first: Unplug the air conditioner from the wall outlet before removing any covers. Capacitors inside can hold a charge; avoid touching exposed terminals.

Steps to check and correct E1:

• Power reset: Unplug the unit for 5 minutes, then plug back in and try again. Sometimes E1 is a temporary logic fault.
• Access the control panel: Remove the front grille and the screws securing the control panel bezel. Carefully lift the panel to expose the control board and sensor wiring.
• Locate the room thermistor: On Whirlpool units it is usually a small bead-type sensor on two thin wires, clipped near the air intake grille or evaporator coil.
• Inspect wiring: Look for broken, pinched, or chewed wires, loose plugs, or corrosion at the connector on the control board. Reseat the connector firmly.
• Check sensor resistance: With the unit unplugged, disconnect the thermistor and measure resistance with a multimeter. At room temperature (around 77°F / 25°C) most Whirlpool NTC sensors read roughly 8–15 kΩ. If it reads open (OL) or near 0 Ω, the sensor is defective.
• Replace if faulty: If readings are out of range, replace the room temperature sensor (thermistor) with a Whirlpool-compatible part. Route the new sensor in the same location and clip it securely away from the coil fins.
• Reassemble and test: Reinstall the control panel and grille, plug in the unit, and run in COOL mode to confirm the E1 code is cleared.

When to call a technician: If the sensor tests good but E1 persists, the main control board sensor circuit may be defective and should be diagnosed and replaced by a qualified technician.