How Do I Know If My Dryer Thermostat is Bad?

As with most appliances, time and use can cause parts to wear down over time, but do-it-yourselfers can often make repairs on their own with relative ease.

Checking the cycling thermostat should be your initial task. Utilize a multimeter to test for continuity at room temperature; if zero or infinity readings appear on its display screen, this thermostat needs replacement.

Heater Element

Breaking heating elements is often at the root of why dryers won’t heat up to dry your clothes properly, making testing straightforward. Simply confirm that all circuit wires are connected to the thermostat and the heater has power (using an electric non-contact circuit tester is recommended for this step) then connect one probe from your multi-tester on OHMs setting to each screw terminal on your heating element; if no continuity exists and/or its needle doesn’t move when conducting continuity tests then that indicates an issue and means that an element needs replacing immediately.

Faulty cycling thermostats can also lead to a dryer not producing heat. This part monitors temperature in the blower housing and cycles heat on and off to maintain airflow; when its accuracy becomes inaccurate, it could stay on too long and overheat the dryer.

Newer dryers may forgoing traditional cycle thermostats in favor of thermistors – this two-wire device transmits variable resistance signal back to the control board that indicates its temperature. Faulty thermistors may fail to switch off, leading to overheating issues with your machine.

Contrary to thermal fuses and high limit thermostats which feature electrical contacts that break when exposed to heat, cycling thermostats feature normally closed contact points that open on temperature rise if the cycling thermostat fails – otherwise heaters or gas burners won’t shut off when scheduled – similar to when they fail thermal fuses (tripped thermal fuse). A multi-tester can be used to test continuity for bias heaters built into cycling thermostats – to find your dryer’s wiring diagram is needed in order to identify an expected ohm range for bias heaters built into cycling thermostats (tripped thermal fuse).

Cycling Thermostat

A dryer’s thermostat is one of the many parts designed to maintain safe temperatures in its environment. Without its service, heating elements or burner assemblies may overheat, leaving its job of switching on/off heat sources in order to prevent them from getting too hot unfulfilled.

If your dryer is no longer producing heat or taking significantly longer to dry a load, its cycling thermostat could be broken. To test it, first verify if its thermal fuse (TF) hasn’t blown.

Find and remove the thermistor from its housing, usually found on a blower housing, usually a small black box with two metal prongs. Set your multimeter to its rated temperature for the thermistor and place one probe on each prong to test if there is continuity between its terminals at room temperature – if this doesn’t exist then your thermistor is bad and needs replacing immediately.

Apart from the thermistor, other heating-control mechanisms include an operating or cycling thermostat and high-limit thermostat that shut off heat sources if they become overheated. Both are easily testable using a multimeter. Once your dryer is unplugged and you locate and unscrew its cycling thermostat (within 135 to 165 degrees Fahrenheit range), use your multimeter to test for continuity using both red probe and black probe probe.

The high-limit thermostat is a safety switch designed to cut electrical contact between operating thermostat and gas burner assembly if it senses that your dryer has become too hot. In general, this switch only shuts off heat sources if there is too little airflow through clogged ductwork, though intermittent failure could occur if contacts fuse together and fail intermittently. Follow similar testing procedures when testing cycling thermostat for continuity if replacing high-limit thermostat is necessary.

High-Limit Thermostat

Safety thermostats, often referred to as high-limit thermostats, are responsible for shutting off the heating element if a dryer becomes too hot, protecting both itself and its users from overheating. When this part fails it may stop functioning properly and should be replaced; causes include restricted air flow or build-up in vent hose or exhaust pipe leading to overheating which in turn trips the thermostat.

Failure may also be caused by a faulty thermistor, an electronic sensor which measures temperature and regulates power to a heater element. A multimeter can be used to check this by measuring resistance between its two terminals – when operating at room temperature a good continuity will register between 0 and 100 Ohms on its resistance gauge.

One common cause of an overheated or unheated dryer can be a blown thermal fuse, the last line of defense for your machine. When this fuse blows, your dryer won’t run at all or with no heat; this could be triggered by cycling thermostat failure, bad thermistor performance or other reasons.

To test a thermal fuse you will first need to disconnect your dryer from its power source, open its cabinet, and locate it – usually inside or near the blower wheel housing. Use a multi-meter to measure continuity; if the reading drops to zero this indicates it has failed and should be replaced as soon as possible.

Troubleshooting dryer problems is easy; simply use a multi-meter to inspect its heating element, cycling thermostat and high-limit thermostat with its respective setting for high/low. If none of this helps solve the problem then professional appliance repair should be called upon immediately to help protect against further damage to the machine.


Timer problems might not seem directly connected with your dryer not producing heat, but they could be at the core of this issue in certain instances. A timer is responsible for controlling the duration of cycles and signalling when to advance to the next one; if this component breaks down then your dryer could continue running until it overheats or won’t advance at all to its next cycle stage.

Faulty timers may be caused by a broken control board. This board contains contacts that connect to the heating element and send current through, so if any of them become dysfunctional, power may no longer reach it; ultimately rendering your thermostat incapable of producing heat.

One of the primary culprits behind a dryer not producing heat is a blown thermal fuse, installed as a safeguard to protect against overheating. Once they’ve been tripped once, they usually require replacement to fully function again – though homeowners must remember why their fuse was initially tripped before performing this simple process; otherwise it could happen again, and possibly result in even less heat being produced from their dryer than originally anticipated.

The thermistor is another component that may be difficult for home owners to diagnose and repair themselves, yet replacing it may help your dryer produce heat more effectively. You can do this by unplugging and opening up the cabinet before using a multi-meter to measure resistance at its terminals – depending on its model of dryer this reading should read zero or infinity; either one would indicate replacement.

As part of your inspection of your dryer’s components, it’s also crucial that all other parts are functioning optimally. If both heater and cycling thermostat are operating as designed, this can narrow down any other potential issues with your appliance. When all else has failed, professional appliance repair services often recommend taking a closer look and offering solutions.