Fix a blower motor that only runs on 1 speed
In this how-to I'll show you how to fix a blower motor (fan inside the car that is part of the HVAC system) that only runs on 1 speed.
This problem is usually caused by a faulty blower resistor. If your fan only runs on the highest speed, but not any other speeds, this problem can be fixed following this how-to.
A blower resistor works by reducing the voltage supplied to the blower motor on low to medium speeds. When your fan is set to the highest setting, the blower resistor is bypassed and full 12v is sent to the fan.
-10mm 1/4" drive shallow socket
-1/4" drive flex head ratchet
ESTIMATED REPAIR TIME:
To verify that you have a faulty blower resistor, disconnect the electrical connector on the blower motor, and use a voltmeter set to DC volts and check for voltage on each speed setting. If voltage only exists on high speed, this confirms a faulty resistor. On this vehicle, the blower motor electrical connection is located underneath the glovebox.
STEP 1: Open the glovebox and press in on both sides at the same time to release the glovebox from the inside of the dash.
STEP 2: Use your flashlight to locate the blower resistor, in this case it's tucked on top of the HVAC box, bit of an awkward position. This is why I recommend using a 1/4" drive flex head ratchet.
STEP 3: Disconnect the electrical connection on the resistor for better access to the 2 10mm bolts that hold it in place. Remove the bolts and remove the resistor.
STEP 4: Replace the resistor, reinstall the 2 10mm bolts. Plug the electrical connection back in. Verify that your blower motor is now working on all speeds. Put your glovebox back into position.