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Eric, Automotive Repair Shop Manager
Category: Ford
Satisfied Customers: 31933
Experience:  Automotive Repair Shop Manager, Technician
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1999 Ford F-150: heater blower switch only works on high

Customer Question

I have a 1999 Ford F-150 the heater blower switch only works on high.. What could be the problem?
Submitted: 7 years ago.
Category: Ford
Expert:  Eric replied 7 years ago.



This is most commonly caused by a faulty blower motor resistor. The high speed is controlled by a high speed relay while the lower speeds are controlled by a resistor that regulates voltage to the blower motor.


It is fairly easy to replace. It is located next to the blower motor underneath the right side of the dash on passenger side. Remove the harness connector to the resistor, remove the 2 retaining screws and pull out old resistor. Install new one in reverse:



Expert:  Eric replied 7 years ago.



Were you able to find the resistor underneath the dash ok? If you have more questions on it, feel free to ask, if not, please click the accept button