Back to all

Such a Little Part (Climate Control Resistor)

December 13, 2020

You expect your heater/air conditioner to work like it should.  You have a control for temperature and one for fan speed.  You even have a control for what vents the air comes out of. 

Don't be surprised one day if your blower fan develops a mind of its own and starts going crazy.  Most of the time, you may find that it starts blowing at full speed, and nothing you do to try to control it does any good.  This is what may be happening.

Your blower motor has an electronic component called a resistor.  It does what its name says; it offers resistance.  When you want the fan to run more slowly, you turn the fan speed down.  That resistor accomplishes that by turning its resistance up.  When the resistor fails, the power has nothing to slow it and the fan speeds up. 

It's a small part and can fail due to age or corrosion.  It's usually not an expensive part, either, but it's often found in a location that's not that easy for the technician to get to.  That means labor costs will vary depending on the design of your vehicle. 

Occasionally, a faulty resistor can cause the blower motor not to work at all or only partially come on.  But other things can cause that as well, such as a faulty fan switch or vent control. 

This is where a technician's training comes in.  Special equipment can track down precisely where the issue is so you can be assured the correct part is being replaced.

It's just not pleasant when the blower motor isn't following orders.  Have your service facility check it out so you can be the blower's boss, like it should be. 

Tuffy Tire & Auto Service Center Appleton
2940 E. College Ave.
Appleton, Wisconsin 54915
920-954-8500

More articles from Tuffy Appleton

(Timing Belt)

March 30, 2025

You may have heard about an important part of your vehicle's engine called a timing belt, and many know that if that belt breaks, it can cause some very serious engine problems. Not all vehicles have them, and the ones that do generally have smaller engines. The timing belt keeps the engine sy... More

Differential Essential (Differential Fluid Exchange)

March 23, 2025

What's the dif? To an automotive technician, it's the differential, a part of your vehicle that helps direct power from the engine to the wheels. The differential is a gearbox that enables the drive wheels to turn at different speeds (they do that when you turn). Inside the differential is a f... More

That Vexing Vapor Venting (Vapor Coming out of Vents)

March 16, 2025

You may have noticed sometimes on a hot and humid day, vapor will come out of your vehicle's vents when you have the air conditioning on. Is that something to be concerned about? Well, it depends. Sometimes that steam or vapor can be caused by water accumulating in the vent system after it has c... More