If your dryer runs through a full cycle but the clothes come out cold and damp, the most likely cause is a clogged exhaust vent restricting airflow. After that, in rough order of likelihood: a blown thermal fuse, a failed heating element (electric dryers), a bad igniter or gas valve coil (gas dryers), or a tripped leg of the 240V circuit breaker (electric dryers only). Most of these you can check yourself without tools. A few need a pro.
Why a clogged vent is the first thing to check
A dryer needs a clear path to exhaust hot, humid air. When lint builds up in the vent hose or the wall duct, airflow slows, heat backs up inside the drum, and the dryer’s high-limit thermostat shuts off the heating circuit as a safety measure. The drum keeps spinning. The heat doesn’t come back on.
The homeowner check: Disconnect the vent hose from the back of the dryer and run a short cycle. If heat returns, the vent is your problem. You can clear a short vent run with a brush kit (available at hardware stores). Runs longer than about 25 feet, or any duct with multiple 90-degree bends, usually need a dryer vent cleaning service.
San Diego homes and condos built in the 1970s and 80s often have long, poorly routed vents that travel through interior walls before exiting. These are prone to lint buildup and are worth cleaning annually. If you’re not sure of your vent layout, that’s a job for a pro.
Blown thermal fuse
The thermal fuse is a one-time safety device. It blows when the dryer overheats, usually because of a clogged vent. Once it blows, the dryer won’t heat at all until the fuse is replaced.
The homeowner check: Unplug the dryer. Remove the back panel (two or three screws on most models). The thermal fuse is a small, oblong part mounted near the exhaust duct or the heating chamber, connected by two wires. You can test it with a multimeter set to continuity: a good fuse reads close to zero ohms; a blown fuse reads “OL” or infinity. Replacement fuses cost $5-$15 and are available at appliance parts stores.
One important note: replacing the fuse without fixing the underlying vent restriction means it will blow again. Clear the vent first.
Failed heating element (electric dryers)
On electric dryers, the heating element is a coiled resistance wire inside a metal housing that generates heat when current passes through it. It’s the direct heat source. When a coil breaks, heat stops entirely.
The homeowner check: Same process as the thermal fuse test. With the dryer unplugged and the back panel off, locate the heating element housing and disconnect its terminals. A working element shows low resistance (roughly 8-50 ohms depending on the model). An “OL” reading means the coil is broken.
For a step-by-step walkthrough of the multimeter test, including how to access the element on common dryer brands, read our dedicated post on dryer heating element testing.
Replacing a heating element is a moderate DIY repair on most dryers. The part runs $40-$150. If you’re not comfortable with electrical components inside an appliance, this one’s worth a call to a dryer repair technician.
Gas dryer: igniter, flame sensor, and gas valve coils
Gas dryers heat differently. A gas valve opens, an igniter glows hot enough to light the gas, and a flame sensor confirms the burner is lit. Any one of these parts failing means no heat, even though the drum spins normally.
The igniter is the most common failure point. You can sometimes see it glow orange through a small observation window on the burner assembly. If it glows but the gas doesn’t ignite, the gas valve coils or flame sensor are the more likely culprits.
Safety note for gas dryers: Don’t attempt to open or test the gas valve or gas supply line yourself. If you smell gas at any point, don’t run the dryer, don’t create any spark, and call your gas company. For igniter and coil diagnosis, a service call is the right call. These parts are inexpensive ($15-$60), and a technician can swap them in under an hour.
Tripped 240V circuit breaker (electric dryers only)
Electric dryers run on a 240V circuit, which uses two separate 120V “legs.” If one leg trips in the breaker panel, the dryer gets power to run the motor and controls, but the heating circuit goes dead. The drum spins. Nothing heats. This is an easy thing to miss.
The check: Go to your breaker panel and look for the double-pole breaker labeled for the dryer. Even if it doesn’t look fully tripped, flip it all the way off, then back on. Run a cycle. If it trips again immediately, there’s a wiring fault that needs an electrician, not an appliance tech.
When to call a professional
Check this against where you are:
| Symptom | Likely cause | Safe to DIY? |
|---|---|---|
| Drum spins, no heat, long cycle times | Clogged vent | Yes, clear short runs yourself |
| Drum spins, no heat, vent is clear | Blown thermal fuse | Yes if comfortable with multimeter |
| Electric dryer, no heat, fuse is good | Failed heating element | Moderate DIY or call a pro |
| Gas dryer, burner doesn’t light | Igniter, coils, or flame sensor | Call a pro |
| Electric dryer, drum spins slowly too | Tripped 240V breaker leg | Check panel first; call electrician if it re-trips |
| Any gas smell | Gas supply issue | Stop immediately, call gas company |
If you’re in San Diego and need a same-day look, our team handles dryer repair across the county. Call (858) 988-7787 for an estimate.
You can also check our guides on gas vs. electric dryer considerations for San Diego homes and dryer vent safety for more context. Or if you’re in North County, we serve dryer repair in Encinitas and surrounding cities.
Frequently asked questions
Why is my dryer running but not heating?
The most common reason is a clogged exhaust vent that’s triggered the high-limit thermostat to shut off the heating circuit. After that, a blown thermal fuse (which doesn’t reset itself), a failed heating element on electric models, or a bad igniter on gas models. On electric dryers, a partially tripped 240V breaker is also worth checking before anything else.
Can a clogged vent stop a dryer from heating?
Yes, and it’s the leading cause. When lint blocks the exhaust duct, heat can’t escape and the dryer’s safety thermostat cuts power to the heating circuit to prevent a fire. The drum keeps running but no heat is produced. Clear the vent and the dryer usually heats normally again. If the vent was badly clogged, the thermal fuse may have blown and will need to be replaced separately.
Does this problem affect gas and electric dryers the same way?
Not quite. Both types can suffer from clogged vents and blown thermal fuses. But the heat source is different. Electric dryers use a resistance heating element that can break or burn out. Gas dryers use a burner assembly with an igniter, flame sensor, and gas valve coils, any of which can fail independently. If your gas dryer runs but won’t heat, start with the vent, then call a technician for the burner components.
How much does it cost to fix a dryer that’s not heating?
It depends on the cause. Clearing a short vent run yourself costs almost nothing. A replacement thermal fuse is $5-$15 in parts. A heating element runs $40-$150 in parts, plus labor if you use a tech. A gas igniter or coil set is usually $15-$60 in parts. Total professional repair costs in San Diego typically fall between $100 and $300 for these repairs, including a diagnostic fee and labor. If the tech finds a failed control board or motor, costs can be higher, worth getting a quote before approving that work.
When should I repair vs. replace the dryer?
A general rule: if the repair cost is more than half the price of a comparable new dryer, replacement is worth considering. For a no-heat issue, most repairs fall well under that threshold. A $150 repair on a dryer that would cost $600 to replace makes sense. Where it gets less clear-cut is when the dryer is over 10 years old and already has other issues. A technician can give you an honest read on what the unit’s worth repairing.