Skip the auto shop - Our mechanics make house calls

Q: Ac not working and car overheating

asked by on

The other day we had the a.c. on and noticed that it was not blowing out cool air, shortly after the car overheated. We took it to the shop where he changed the thermostat and a fan. The a.c. still does not work. We tried the a.c. again and once again the car overheated. We have drove the car several times with out the a.c. and it does not overheat. Only when you mess with the a.c. does it overheat. If a fan and thermostat has been changed what is causing the overheating?
My car has an automatic transmission.

A: The two cooling fans are controlled by a fa...

The two cooling fans are controlled by a fan controller which is mounted in the center of the engine, above the radiator. The fan controller controls the fan speeds depending on the signals from the engine control module input. A scan of the computer input and output may point to a problem with the fan controller not turning on the fans when the A/C is turned on or the ECM is not turning on the fan controller when the A/C is turned on. You will need to have the system scanned with a device that can test the fan controller and ECM operation. This may take a factory level scanner to properly diagnose the problem. I'd suggest getting some assistance from a certified mechanic who can pinpoint your overheating issue and address your A/C problem as well.

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・Save up to 30%

Get a quote

What others are asking

Q: Hot air mixed with cold blows from air conditioning

Hey there. You will most likely have to have a mechanic bypass the heater coolant lines to have this resolved. Your A/C may not be controlling the air flow inside the evaporator correctly out of the vents and may be...

Q: Oil or some sort of black sludge covering CV axle, control arm, etc.

After looking at the pictures you took, it looks to me like the inner axle boot has been slinging out grease from the CV joint. I recommend you clean off the inner CV boot and look for a loose or...

Q: Broke down on the highway and had towed to a Buick dealer. They diagnosed and replaced the catalytic converter.

It is possible that the new catalytic converter is bad. Sometimes, when the converter comes apart inside, it can get into the muffler and cause it to be clogged.

Related articles

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.
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.