If your fan speed control is not working, it means you can’t adjust the airflow from your vehicle’s heating, ventilation, and air conditioning (HVAC) system. This may result in the fan only working on one speed, not working at all, or being stuck at full blast. The issue is usually electrical and requires an inspection to determine the cause.

What does it mean if the fan speed control isn’t working?

This problem usually points to a fault in the blower motor resistor, fan switch, wiring, or the blower motor itself. In modern vehicles, it could also be due to a failure in the HVAC control module.

Common causes of fan speed control not working

• Faulty blower motor resistor (common cause)
• Blown fuse or faulty relay
• Damaged fan speed control switch
• Worn or faulty blower motor
• Electrical wiring faults or loose connections
• HVAC control module failure (in some vehicles)

Why do you need to fix this problem quickly?

Without working fan speed control, you may not be able to defog the windscreen properly, heat the car in winter, or cool it in summer. This impacts comfort, visibility, and safety while driving.

How do you know when to get it checked?

You should book an assessment if:

• The fan only works on one speed setting (often high)
• The fan does not blow air at all
• You can’t adjust airflow strength inside the cabin
• The fan speed changes on its own
• The HVAC controls feel loose or unresponsive

What happens during an assessment?

A mechanic will:

1. Test the blower motor and speed settings
2. Check fuses, relays, and wiring connections
3. Inspect the blower motor resistor or control module
4. Test the fan speed switch for proper function
5. Replace the faulty component causing the issue
6. Confirm that all fan speeds work correctly after repair

How much does it cost to fix?

Blower motor resistor replacement typically costs $180–$400. If the blower motor or HVAC control module is faulty, repairs may cost $400–$1,000+, depending on the vehicle.

Is it unsafe to drive with fan speed control not working?

Yes. While the car will still run, lack of airflow control can reduce comfort and make it difficult to clear the windscreen in poor weather, creating safety risks. It should be repaired as soon as possible.