Blower Motor Replacement: Motor, Resistor or Fuse?

What does the blower motor do?

The blower motor is the electric fan that pushes air through your heater and air conditioning and out of the dash vents. The heater core warms the air and the AC cools it, but without the blower, very little of that air reaches you. It also moves air across the windshield for defrosting.

The fan speed is set by a part called the blower motor resistor, or on many newer cars with automatic climate control, an electronic control module. Standard Motor Products, a maker of these parts, explains that the resistor controls the current flowing from the fan switch to the blower, which is how you get different speeds. Newer systems use electronic control modules and solid-state controls instead of simple resistor circuits.

Is it the blower motor, the resistor, or something else?

When the fan acts up, the blower motor is only one suspect. The pattern of the problem is a useful clue:

The “high only” clue comes from how the circuit works. According to Standard Motor Products, when high speed is selected the resistor is bypassed and the blower motor is connected straight to ground, so the fan gets maximum current. That’s why a car with a failed resistor often still blows on high.

The motor and resistor are linked. Standard Motor Products notes that worn-out blower motors can draw too much current, and that if the current is too high the blower motor should be replaced too, or the new resistor or control assembly will fail again. Four Seasons adds that moisture and contaminants entering the fresh air intake can corrode the resistor’s terminals, and that the connector itself can struggle to carry higher current for long periods. A good mechanic checks the motor’s current draw and the connector, not just the resistor.

If the air moves but isn’t cold, see our guide to AC blowing warm air and the car AC recharge service. If you smell something burning from the vents, stop using the fan and have the car checked before using the fan again.

What are the signs you need blower motor replacement?

• No air from the vents at any fan speed, after the fuse and relay have been checked.
• Noise such as squealing, rattling or ticking from behind the glove box or dash that changes with fan speed.
• Fan that cuts in and out or needs a bump to start.
• Weak airflow that doesn’t improve with a new cabin air filter.
• A resistor that keeps failing, which can point to a worn motor drawing too much current.

A working fan matters for more than comfort: it clears fog and frost from the windshield. If the defroster can’t clear the glass, don’t drive until you can see properly.

Can a mobile mechanic replace a blower motor in your driveway?

Usually, yes. Blower motors, resistors, fuses and relays are all electrical parts that a mobile mechanic can reach with hand tools, a multimeter and a scan tool. No lift is needed.

How long it takes depends on the car. On some vehicles the blower motor comes out from under the dash after a few screws and a trim panel. On others, parts of the dashboard, the glove box or other components have to come out first, which adds time. Work around the dashboard can be near airbag components and wiring, which is one more reason to leave it to a professional. Give the mechanic your exact year, make and model so they can check the procedure before the visit.

If the problem turns out to be inside the climate control module or deep in the dash wiring, it may take longer to trace, and a few repairs may be sent to a shop or dealer. See what a mobile mechanic can and can’t do.

What does the job involve?

1. Diagnose. The mechanic checks the fuse and relay, tests power and ground at the blower, checks the resistor or module, and looks at the cabin air filter. If it isn’t obvious, this may be a diagnostic visit.
2. Quote. You get a price for parts and labor before work starts. Ask for a written estimate.
3. Access. The battery may be disconnected, and trim panels or the glove box are removed to reach the blower.
4. Replace. The old motor (and resistor or connector, if needed) comes out and the new one goes in.
5. Test. Every fan speed and vent mode is tested, including defrost, and the panels go back on.

A clogged cabin air filter can make any blower sound strained and cut airflow. Filter intervals vary by car; Honda’s 2018 CR-V schedule, for example, says to replace the dust and pollen filter every 15,000 miles if you drive mostly in urban areas with a lot of soot in the air. See air filter replacement.

How much does blower motor replacement cost?

Blower motor replacement has no row in this site’s standard price table, because the part price and the time to reach it vary so much between vehicles. The mechanic quotes after looking. Rates that often apply, from the prices that mechanics we list publish on their own websites:

A resistor, fuse or relay is often a smaller bill than the motor itself. See mobile mechanic cost for the full table.

What should you ask before booking?

• Did you test the motor’s current draw, or just the resistor?
• If it’s the resistor, should the motor and connector be replaced too?
• Is the part OEM or aftermarket?
• How much of the dash has to come apart on my car?
• Will you check the cabin air filter while you’re in there?
• Is there a trip fee, and what warranty covers the parts and labor?

A mechanic who can see the car will know more than any guide.

What to do next

Note exactly what the fan does at each speed before you call; it saves diagnostic time. Then find a mobile mechanic in your city, or send a request with your year, make and model and a short description, such as “works only on high” or “no air at all”.