Keep every blower speed working with the Standard Ignition HVAC Blower Motor Resistor RU-439 (also written RU439), a direct-fit replacement designed for Ford applications. It drops into a wide range of classic Ford trucks, including the 1980-1986 Bronco, 1980-1983 F-100, 1980-1989 F-150 and F-350, 1980-1986 F-250, 1983-1990 F-600, F-700 and F-800, 1988-1989 F-Super Duty, and more — see the Buyer's Guide tab for the full list of covered years and models.
The blower motor resistor steps down voltage to the blower motor so it runs at the lower fan settings; when it fails, you often lose one or more speeds while high may still work.
- Premium copper connectors: deliver more precise resistance values for improved performance and longer part life.
- Kanthal D resistor wire: provides greater flexibility, durability, and tensile strength in the wiring attached to higher-watt resistors.
- Variable speed control: restores A/C and heater blower motor variable speed control, helping to optimize HVAC performance and passenger comfort.
- Tested integration: designed for seamless integration with the vehicle's HVAC system and extensively tested for correct performance.
Interchange: RU1132 · JA1518 · BR342 · E3TZ19A706B
This part cross-references / interchanges with the following part numbers:
Frequently Asked Questions
What does this blower motor resistor do?
It varies the resistance in the blower motor circuit to control fan speed, restoring A/C and heater blower motor variable speed control across the lower settings.
What are signs my blower motor resistor may need replacing?
Losing one or more fan speeds while high may still work is a common sign. Diagnose the cause first, since wiring or the switch can also be involved.
Will the RU-439 fit my Ford?
It's designed for Ford applications like the 1980-1986 Bronco, 1980-1989 F-150 and F-350, and 1983-1990 F-600/F-700/F-800. Check the Buyer's Guide tab for the full list.
What numbers does this part interchange with?
It cross-references RU1132, JA1518, BR342, and E3TZ19A706B.
What is the resistor wire made from?
It uses Kanthal D resistor wire, which provides greater flexibility, durability, and tensile strength in the wiring attached to higher-watt resistors.
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