Maytag Dishwasher Thermostat Replacement Guide

The key to this repair is not confusing the two components, because they cause opposite problems. The thermistor manages temperature, and when it drifts the board mismanages the heating element. The high-limit is a last-resort cutoff that, once tripped, kills the element entirely.

Thermistor vs. high-limit#

The thermistor changes resistance with water temperature — roughly 50,000 ohms at room temperature and about 7,000 ohms at 150°F — and the board reads that resistance as a temperature to decide when to run the element. A drifted thermistor lies to the board. The high-limit thermostat is a bimetallic disc near the element that opens permanently if the water passes about 195°F, and it does not reset; its only job is preventing scalding and element damage.

Reading the symptoms#

• Water never gets hot, dishes greasy — the thermistor reads high, so the board thinks the water is already hot and never fires the element
• Sanitize cycle fails on a temperature error — the thermistor cannot confirm the water reached 150°F, so the board aborts
• Steam billows when you open the door — the thermistor reads low, so the board overheats the water
• Element never heats at all — the high-limit has tripped and cut power to the element
• Erratic cycle times — an intermittent thermistor connection sends fluctuating readings

Test the thermistor on resistance: at about 70°F room temperature it should read roughly 45,000 to 55,000 ohms. Infinite, zero, or wildly off means it failed. Test the high-limit on continuity — it should read closed unless it has tripped, in which case it reads open.

Replacing the parts#

Both are reached the same way: disconnect power at the breaker and remove the lower kickplate to expose the sump.

• Thermistor — it is a small probe in the sump housing on a two-wire harness. Unplug it, release the push-clip or twist-lock, clean any scale from the seat, and seat the new probe fully in the water path.
• High-limit — a small disc near the element terminals. Confirm it is actually tripped (no continuity) before swapping, then transfer the two wires and the mounting screw to the new disc.

Refit the kickplate, restore power, and run a Sanitize cycle to confirm the new part reads correctly. Tools: a 1/4-inch hex driver, Phillips #2, and a multimeter.

The trap to avoid#

A tripped high-limit is usually a symptom, not the root cause. It trips because something else overheated the water — most often a thermistor that read low and drove the element too long. So if you find a tripped high-limit, test the thermistor too; replacing only the disc without fixing the sensor just sets up the new disc to trip again. Maytag builds these on the Whirlpool Corporation platform, so both parts often cross-reference to a Whirlpool W10 or WP number at a lower price — search both when you order.

Confirm it in diagnostic mode#

Before ordering either part, use the Whirlpool-platform diagnostic mode — the entry sequence is printed on the tech-sheet label inside the console, visible along the top edge when the door is open. It reports stored fault codes and live sensor readings, so you can watch the thermistor's value during a cycle and confirm the drift instead of guessing. That matters most for the sanitize cycle, the first program to fail when the sensor is off: the board will not certify the load unless it sees the water actually reach temperature, so a thermistor reading even a little high stops sanitize cold. Fix the sensor and the cycle behaves again, and because these parts are inexpensive, replacing a marginal thermistor preventively is usually the economical call.