Q: AC/heater fan runs constantly even with switch off

asked by on

Lost fan speed control and fan keeps blowing even with the switch off. AC still works but AC fan keeps blowing

My car has 138000 miles.
My car has an automatic transmission.

The most common cause of this problem is the blower motor control processor mounted in the A/C evaporator case. I’d start by checking that first I were you. I you need some assistance however, feel free to contact a professional mechanic who can diagnose your A/C system firsthand and make the necessary repairs.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. AC/heater fan runs constantly even with switch off

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: Front engine seal is leaking

Hello, if the front crankshaft seal is leaking, the only way to stop the leak is to replace the seal. The harmonic damper needs to removed for access to the seal. Other parts may have to be removed like the...

Q: Q: Why Is My AC Blowing Warm Air?

There are quite a few reasons an A/C system will cease to provide you with cold air. Air conditioning systems are one of the more complex systems on a passenger vehicle. Without getting into to all the complexities and science...

Q: Q: How do I use the air conditioning?

The air conditioning system brings cold air into your vehicle, to help keep you cool on hot days. To turn on the air conditioning, press the A/C button in the middle of the Fan Speed Control knob. A light will...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
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...