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Also known as: Interior blower resistor, Interior Blower Resistor, Blower Motor Resistor, Fan Speed Resistor

OEM & aftermarket heater blower resistor from top brands — compare prices, check fitment, order with free delivery

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Shop 1798 heater blower resistor from 24 trusted brands including NTY, KAMOKA, ESEN SKV. Compare prices, check vehicle compatibility, and get free delivery on orders over £99.

Heater Blower Resistor for the top car models

Audi2970

Heater Blower Resistor buying guide — what to know before you buy

The heater blower resistor — also called the blower resistor, fan resistor, blower motor resistor, or series resistor — controls the speed of the cabin heater fan by adding electrical resistance to the motor circuit. On vehicles without electronic climate control, the resistor pack provides the lower fan speeds (1, 2, 3) while the highest speed bypasses the resistor entirely. When the resistor fails, the fan often works only on its highest setting or stops entirely. CarParts247 stocks OEM and aftermarket heater blower resistors from Hella, Siemens VDO, and Febi Bilstein for a broad range of vehicles.

How to identify a failed blower resistor

The most common failure pattern is loss of one or more lower fan speeds while the highest speed continues to work. This is because maximum speed bypasses the resistor pack through a direct relay, leaving only the resistor-controlled speeds affected.

Fan works on speed 4 only — classic resistor failure
Fan does not work at all — resistor and relay both failed
Fan works only on low speeds — relay failed, upper speeds lost
Burning smell from the heater vents — resistor overheating before failure

Replacement procedure

The blower resistor is typically mounted in the heater plenum, accessible from the footwell on either the driver or passenger side. Remove the electrical connector and the one or two retaining screws, slide the old unit out, and fit the new resistor in the same orientation. On some vehicles the resistor is cooled by the heater fan airflow — ensure the cooling fins face into the airstream.

Check the blower motor current draw before fitting the new resistor — an overloaded motor burning out resistors repeatedly points to a worn motor
Inspect the connector pins for overheating damage — black or melted plastic requires connector repair
Test all fan speeds immediately after fitting

Frequently Asked Questions

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Why does my heater fan only work on the highest setting?

This is the classic heater blower resistor failure. Speed 4 (maximum) bypasses the resistor through a relay, so when the resistor pack burns out speeds 1, 2, and 3 are lost but speed 4 remains.

Can I drive with a failed heater blower resistor?

Yes, but only maximum fan speed will be available. This is particularly inconvenient in summer as the climate control cannot reduce fan speed. Replace the resistor for full comfort control.

Is the heater blower resistor the same on climate control cars?

Vehicles with full automatic climate control use a PWM (pulse-width modulation) fan speed controller rather than a fixed resistor pack. The replacement part and diagnostic procedure are different.

How long does a heater blower resistor last?

Most last 80,000 to 150,000 miles, but a worn blower motor that draws excessive current can destroy a resistor within months. Always check motor current before condemning the resistor.