Description
Product Overview
The Heater Fan Regulator (Part 644178) controls the speed of the cabin blower motor on a range of PSA (Citroën & Peugeot) vehicles. Manufactured by Valeo, it ensures selectable fan speeds for heating and ventilation systems. Often referenced by the part number 644178, this unit restores consistent blower performance when the original module fails.
Compatibility
Symptoms Of A Faulty Regulator
- Loss of some or all fan speeds (blower works only on high or not at all)
- Intermittent operation or fan stuck on a single speed
- Burnt smell from the dashboard or visible corrosion on the connector
Why They Fail
Common failure causes include heat-related degradation of resistive elements or electronic components, corrosion from moisture ingress, poor electrical contact at the connector, or wiring issues. Over time these lead to increased resistance, heat build-up and eventual open circuit.
Replacement And Installation Notes
Replacement is straightforward for a competent mechanic or DIY enthusiast. Typically located in the blower motor housing under the dashboard or behind the glovebox, the unit is secured with a few screws and an electrical connector. Steps: disconnect the battery, remove trim or glovebox as required, unplug the connector, unscrew and swap the regulator, then reassemble. Verify operation at all fan speeds after installation.
Technical Information
- Manufacturer: Valeo
- Model: Heater Fan Regulator (Blower Motor Resistor / Fan Speed Regulator)
- Product Codes: 644178
- Additional Numbers: 644178
Notes
Always match the part number 644178 to ensure fitment. If unsure, check the vehicle VIN or consult a parts specialist. Replacing a faulty regulator typically restores full heater and ventilation control.
