This is the replacement blower motor resistor I installed on my 1966 Mustang heater box. The resistor is what gives the heater fan its different speeds, working with the fan switch on the dash.
It mounts on the face of the heater box, and it’s easiest to replace while the box is out of the car.
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Blower Motor Resistor at a Glance
- Replacement blower motor resistor for 1965-1966 Mustangs
- Controls the heater fan speeds with the dash switch
- Mounts on the face of the heater box
Why I Replaced Mine
When I had my heater box on the bench, my plan was a gasket kit, a new motor, a cleanup and a new resistor. The original resistor and its connector were over 50 years old, and it’s a cheap part to swap while everything is apart.
Replacing it now means I won’t have to pull the box again if a fan speed quits.
Who This Resistor Is For
- Owners whose heater fan only works on some speeds
- Anyone doing a full heater box rebuild
- Anyone replacing the blower motor
How I Installed It
- Unplug the wiring from the old resistor on the heater box.
- Remove the old resistor from the box.
- Mount the new resistor in the same spot.
- Reconnect the wiring and test each fan speed after the box is reinstalled.
See It in Action
I installed this resistor in my 1965-1966 Mustang Heater Box Rebuild. The post and video cover the full rebuild.