Symptoms
- No air comes out of any vent regardless of fan speed
- Fan works on high but not lower speeds, or vice versa
- Clicking or grinding noise from under the dash
- Fan works intermittently or cuts out while driving
Likely causes
- CommonBlown blower motor fuseA dedicated fuse for the blower circuit can blow, disabling all fan speeds.
- CommonFailed blower motor resistorThis part controls different fan speeds and often fails, commonly leaving only the highest speed working.
- CommonWorn out blower motorThe motor itself can wear out from age, debris, or a failing bearing.
- PossibleDebris blocking the blower wheelLeaves or debris pulled in through the cabin air intake can jam the fan wheel.
- PossibleFaulty blower control module (on automatic climate systems)Some vehicles use a more complex module instead of a simple resistor.
What to do
- Check the fuse box for a blown blower motor fuse and replace with the correct amperage.
- Test all fan speed settings; if only the highest speed works, the blower resistor is a likely cause.
- Listen closely near the blower motor (usually under the dash on the passenger side) for a clicking, grinding, or straining sound.
- Check the cabin air filter and intake area for debris that could be jamming the fan wheel.
- Note if the fan cuts out intermittently, especially over bumps, which can suggest a wiring or connector issue.
- Avoid running the blower on high only as a permanent workaround, since it strains the motor and doesn't fix the resistor issue.
- Have a shop replace the blower motor resistor or module if speed-specific failure is confirmed.
- Replace the blower motor itself if it's confirmed worn out or making abnormal noise.
Tools and parts
- Fuse puller or pliers
- Replacement fuses
- Flashlight
Blower motor resistorSearch: “blower motor resistor for [your car make model year]”
Blower motorSearch: “HVAC blower motor for [your car make model year]”
When to call a pro
If access to the blower motor is difficult on your vehicle, a shop can replace it along with checking the resistor or module in one visit.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.