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Is this heater blower motor resistor problem? (2006 Ford Focus)

The problem with my 2006 Ford Focus looks like a heater blower motor problem. But I am not sure.
I have a regular turn-the-knob type of heater/AC not the electronic type. The blower speed setting has 4 steps, and it does not function on the lowest setting 1, but 2, 3 and 4 work fine. I thought the blower motor resistor is faulty when it blows at the highest setting or does not blow at all. With mine, only the lowest setting is not working and the rest are fine. Is this also a blower motor resistor problem?

Thank you in advance for answering my question.

The blower resistor passes the voltage thru a series of resistors.

The lowest speed the voltage passes thru three resistors. The next highest speed it passes thru two resistors. The next highest speed it passes thru one resistor. At the highest speed, the voltage doesn’t pass thru the resistors at all. The blower relay directs the voltage directly to the blower motor.

Replace the blower resistor.

Tester

2 Likes

Agree with tester, Did not know mine was out until no cool at stops, as 1 was where we usually left it!

That makes perfect sense! Thank you. I only heard that when the blower resistor is bad, the fan would run only at highest speed. But no one explained to me why that is. Thank you very much.

The “1” speed has been out of commission on my Corolla for years. I just use the “2” instead. With blower-motor resistor type designs (as opposed to electronic speed control) the available power is divided between the resistor and the blower motor. For the highest speed all the power goes to the blower motor, none to the resistor, and for the lowest speed most of the power goes to the resistor, only a little to the motor. This heats the resistor & is why it usually stops working on the first speed. It’s usually an inexpensive and easy part to replace, on the order of 1/2 hour and maybe $40 for the part.