Skip the auto shop - Our mechanics make house calls

Q: Blower motor randomly works

asked by on

The blower motor is randomly working. While searching for a solution, I jiggled the wires under the dash and that seemed to help slightly. Even after the dealership replaced the motor, still had the same problem. It’s a 3-terminal motor and I’m assuming it has on-board transistor diode pair of PWM operation. Is it a N-channel or P-channel FET and would tying the transistor gate to one of the other pins turn the motor to full blast?

The blower speed is controlled by a final stage unit sometimes referred to as a blower resistor by an auto parts store. This is located on the passenger side of the heater box and has probably failed. A lot of times this unit can fail due a faulty blower motor that has been drawing a lot of current during its operation. You may want to enlist the help of a mechanic, such as one from YourMechanic, who will have the tools and expertise to diagnose the blower circuit and correct the blower issue.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. Blower motor randomly works

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: my back tire feel f they comeing off when i make turn left and right

Hi there. In most cases, this problem is caused by damaged wheel bearings or damaged rear struts. When this type of problem occurs, it's critical to repair it as soon as possible. The best way to know for certain what...

Q: Today My AC Just Stopped working,Took It To Auto Parts Store And THEY Checked FUSES And Said THEY Were Good ,Any SUGGESTIONS ?

Hi there, thanks for writing in. The fuses are only a small part of the A/C and climate control system. If the blower still works but the A/C is inoperative, the system pressures will first need to be checked using...

Q: oil pan gasket replacement cost

Hello, thank you for writing in. The oil pan gasket can be tricky to replace. Quoting an exact price for this service can also be tricky. Removing the oil pan to access the gasket is the hardest part, and can...

Related articles

P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.