Blower Motor Replacement
How are blower motor issues diagnosed?
If the blower motor is making a grinding or rattling noise, it will be removed first for inspection. If it's defective, it will be replaced.
If the blower motor isn't blowing air, the technician will first find and inspect any related fuses. If that's not the issue, the blower motor’s electrical connector is inspected to determine if power is reaching the motor. If that's not the problem, the blower motor will be removed and tested with an external power source. If the blower motor fails to operate under direct power, it will be replaced.
How is a heater blower motor replaced?
If the blower motor must be replaced, either the glove box or lower cover will be removed from the dashboard. This will provide access to the HVAC duct box, and the blower motor service cover.
The service cover is removed, and the blower motor is disconnected electronically. Finally, the retaining screws will be removed, followed by the blower motor.
The blower motor resistor will be installed into the new motor, and then they will be installed using the reverse of the procedure above.
What to look out for when dealing with heater blower motor issues
If the blower motor is making noise, you should still be able to use the air conditioner. The motor will eventually fail once the noise has started, but until the vehicle is repaired or the blower motor fails, further use shouldn't cause new problems.
The blower motor resistor can cause similar symptoms, but the fan would more than likely work on one or more settings until the resistor fails. When all fan speeds are not functioning, the blower motor is the likely culprit.
Can I replace the heater blower motor myself?
This procedure is best left to an fairly advanced DIYer or a professional. A basic understanding of a series electrical circuit, a few basic tools and a digital voltage meter are required.
But diagnosis can be tricky, and there's significant labor involved in terms of removing the dash.