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Car Heater Repair Tips: Fixing a Blower Motor

Updated: Aug. 11, 2023

Restore multiple speeds with a simple replacement part

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FH08JAU_BLOMOT_01-2 heater blower motorFamily Handyman
Restore multiple speeds to your auto heater/air conditioner blower by replacing a resistor module. It's a simple, quick change-out.

By the DIY experts of The Family Handyman Magazine

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Restore multiple speeds to your heater blower motor

Resistor module replacement

Remove the electrical connector, retaining screws and the old resistor module. Swap in the new part and reinstall the screws and connector.

Most car manufacturers use a series of resistors to make the heater blower motor run at different speeds. And when one or more of these resistors burn out, you’re usually left with only one heater blower motor speed—high. The resistor module is easy and inexpensive to replace. It’s then typically installed in the ductwork, near the car blower—either under the dash or under the hood. (Refer to a service manual to locate yours.)

Purchase a new resistor module at the auto parts store (usually less than $25). Disconnect the electrical connector. Remove the screws, and swap out the resistor module. Reconnect the electrical connector and you’re car heater blower motor is back in business. See 100 other super simple car repairs you can do on your own and avoid a trip to the shop.

Required Tools for this Project

Have the necessary tools for this DIY car blower motor project lined up before you start—you’ll save time and frustration.

  • 4-in-1 screwdriver
  • Nut driver
You may also need a trouble light.

Required Materials for this Project

Avoid last-minute shopping trips by having all your materials ready ahead of time for this car blower motor repair. Here’s a list.

  • New resistor module

Originally Published: December 17, 2018