Rick's Free Auto Repair Advice

Compressor clutch not engaging after blower resistor replacement

Compressor clutch not engaging after blower resistor

Shops are reporting a high incidence of the AC compressor clutch not engaging after blower motor resistor replacement.

Fix: Make sure you’ve installed the right blower motor resistor. The resistor for a manual temp control versus automatic temperature control can cause the AC compressor no engaging condition. That’s because the HVAC head monitors the return voltage from the blower motor resistor. If the voltage isn’t right, the HVAC head will assume the blower motor isn’t working properly and will prevent AC compressor clutch engagement.

USE OEM resistors

Shops are also finding that many aftermarket resistors cause the problem even when they’re specific to the type of temp control system. When swapping the aftermarket resistor for an OEM part, the problem disappears.

©, 2020 Rick Muscoplat

Posted on by Rick Muscoplat

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