Skip the auto shop - Our mechanics make house calls

Q: Cooling fans running all of the time

asked by on

My cooling fans start immediately when I start the car, even on cold days, and stay on until I turn the engine off.

A: There are a couple possibilities. The engin...

There are a couple possibilities. The engine’s computer controls the fans. If it does not have the proper input from the coolant temp sensor or other vital sensors, it can turn the fans on all the time by default. The Check Engine Light is most likely be on. The other most likely problem would be a faulty fan relay. It could be stuck on. The relay only has source power when the key is turned on. Either way, scanning the car’s computer would narrow down where to look for the culprit.

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!

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: Fan runs when car is off. Overheats when idling for a 3-minute period

Hey there. This can be caused by a number of things such as low coolant levels, a faulty thermostat, or a failing coolant fan switch. As you may know, the coolant fan switch helps to maintain the proper coolant temperature...

Q: Pinking rattles when accelerating

Hello there, thank you for asking about your 2003 BMW 760Li. Spark knock, or pinging, can result from excessive carbon build up. There is a technical service bulletin (TSB) regarding this condition for your vehicle: SI B 11 11 06....

Q: Car fans stopped working

The brake pads on most vehicles are metallic type brake pads and may exhibit a metal grinding sound that may be normal or the brake pad being worn can make the same sound. The best recommendation is to have your...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
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...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.