GE Dishwasher Thermostat Replacement — Temperature Regulation and Safety

Your GE dishwasher uses thermostats to monitor and regulate water temperature at two critical points: the operating thermostat tells the control board when water has reached wash temperature, and the high-limit thermostat shuts down the heating element if water exceeds safe limits. When either fails, the result is either cold washes or an overheating safety shutdown.

Two Types of Thermostats

GE dishwashers have two distinct thermostat functions:

Operating thermostat (thermistor) — a variable-resistance sensor that reports water temperature to the control board continuously. The board uses this reading to decide when to activate and deactivate the heating element. Failure modes: reads too low (element runs continuously, water overheats), reads too high (element never activates, water stays cold), or no reading (board defaults to a fixed cycle without temperature control).

High-limit thermostat (safety cutoff) — a fixed-temperature switch that opens the heating element circuit if water exceeds approximately 185-195 degrees F. This is a safety device that prevents scalding and tub damage. It does not reset automatically on most GE models — once it trips, the element stays off until the thermostat is replaced.

Symptoms by Thermostat Type

Operating Thermostat Failure

• Cold water washes — detergent does not dissolve, grease remains on dishes
• Sanitize cycle aborts with error — the board cannot detect the 155 degrees F required temperature
• Excessively long cycles — the board keeps running the heater waiting for a temperature reading that never comes
• Overheating water — the sensor reads low, so the board runs the element past safe temperatures (high-limit thermostat should catch this as a backup)

High-Limit Thermostat Tripped

• No heat at all — the element worked yesterday but today produces zero heat. The water fills and the motor runs normally.
• Element tests good — multimeter shows 15-30 ohms on the element, but it does not heat. The high-limit thermostat has opened the circuit.

Testing the Thermostats

Operating Thermostat (Thermistor)

At room temperature (~72 degrees F), the thermistor should read approximately 50,000 ohms (50K). This value decreases as temperature rises — in hot water (120 degrees F), it should read approximately 10,000 ohms. A reading of open circuit (OL) or zero ohms indicates failure.

High-Limit Thermostat

Test with a multimeter set to continuity. At room temperature, a good high-limit thermostat shows continuity (closed circuit). If it reads open circuit, it has tripped and needs replacement.

Part Numbers and Pricing

Tools Required

Phillips #2 screwdriver, 1/4-inch nut driver for kick plate, multimeter for testing, and towels for residual water.

Step-by-Step Replacement

Preparation

Disconnect power at the breaker. Allow the dishwasher to cool completely if a cycle recently ran.

Locating the Thermostats

Both thermostats are mounted in the sump area at the bottom of the dishwasher. Remove the kick plate for access from the front, and remove the lower spray arm and filter assembly for access from inside the tub. The operating thermostat is a small probe inserted into the sump with a 2-wire connector. The high-limit thermostat is typically mounted on the heating element housing or the sump exterior.

Removing the Old Thermostat

Disconnect the wire harness. Remove the retaining clip or screw securing the thermostat to the sump. Pull the thermostat from its mounting. Note: the operating thermostat probe must seat fully in the sump for accurate readings — if the previous thermostat was partially dislodged, that alone could explain temperature control problems.

Installing the New Thermostat

Insert the new thermostat into the sump mounting, ensuring the sensing probe is fully submerged in the water flow path. Secure with the retaining clip. Reconnect the wire harness.

Testing

Restore power. Run a Normal cycle and verify the water temperature with an instant-read thermometer held in the water stream when the door is cracked open during the wash phase. Target is 130-145 degrees F for a Normal cycle. Run a Sanitize cycle to verify the element heats to 155 degrees F (the cycle will complete without error if temperature control is working).

High-Limit Thermostat: Root Cause

If the high-limit thermostat has tripped, replacing it restores function — but investigate why it tripped. The most common causes: a failed operating thermostat that let the element run unchecked, a stuck relay on the control board that kept the element energized, or extremely hard water scale insulating the element and causing it to overheat locally. Address the root cause or the new high-limit will trip again.

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Temperature problems affect both cleaning and safety. Our technicians test both thermostats and the heating element circuit in a single diagnostic visit. Schedule service