Q: Radiator fan not working when a/c is on.

asked by on

Hello. Car does not overheats, cause I notice the fan running when car is at operating temperature, but when I turn a/c at cold setting, fan doesn't run. It's supposed to run when the a/c clutch is engaged. A/C system was checked and is fully charged and cabin gets cold when car is moving, but at traffic, or when car is stopped, air starts to blow warmer. I imagine the same fan has 2 speeds, but I need a way to troubleshoot the failure. I'm going to chek the relay today, but some people tell me this car has a control module for the fan operation? Don't want to damage parts, and the dealer is too far awai from me. Thanks in advance for any reply.

My car has 33000 miles.
My car has a manual transmission.

Your vehicle fan is controlled by two different relays in the engine compartment fuse box. One is for low speed and the other is for high speed. The ECM controls both of the relays. The wires to the cooling fan motor are black (ground) brown (high speed) green with white stripe (low speed). With the engine running and the A/C turned on, check for power getting to the low or high power wires to the cooling fan motor.

If you do not have power to the low power wire, then try to replace the relay first. You may be able to temporarily swap the high and low speed relays to test to see if fan is coming on with A/C on. If it does, then try and replace both relays since they may both be burnt. If you find you are getting power to the cooling fan motor but it is not turning, then you have a defective motor. If you do not have power and the relay swap did not work, then you will need to have the computer checked to see if its able to turn on and off the fan using a dealer scanner. The problem is most likely the relay or fan motor.

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. Radiator fan not working when a/c is on.

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: Dealership is telling me my radiator is cracked and leaking. Is it safe to drive to another shop?

It can not be determined to be safe by the information given. The amount of fluid leaking out and how fast it leaks out is not given. Also how far the next shop is was not given. If you drive...

Q: Truck will not start, but lights still work - 1979 Ford F-100

Considering the loud clicking, have the battery tested and charged just to be sure. A loud clicking from the engine bay is a symptom of a failed or weak starter, low charge on the battery or a grounding problem in...

Q: I hear a light metal scrapping on metal as I drive only. It stops when the wheels stop. Starts again as the car moves and sounds

Hello, thank you for writing in. These are classic signs of a brake issue. There are several problems that may be occurring, and you will have to take the wheel off to get a better look. However, resolving the problem...

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...
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...
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...