Skip the auto shop - Our mechanics make house calls

Q: Issue with my A/C, what is the most likely problem?

asked by on

My trucks ac has worked flawlessly all summer this mornitwas the first real cold snap. I adjusted the temperature to warm this morning on the way to work this afternoon when I got back in the truck the air will do nothing but blow warm air. I have checked all fuses I have checked the fan and compressor they Both activate when the ac is turned on. I have no reason to believe I'm low on coolant it has always blown very cold. I suspect the temp control module has malfunctioned because there is no noticeable change in temperature when I turn it all the way to hot or cold. How do I test my theory

My car has 76000 miles.

Hi there. In many cases when the AC suddenly stops blowing cool air, it’s due to a faulty temperature control module (as you indicated) or you’ve developed a vacuum leak somewhere in the system.

You can test this by completed an AC performance test using a manifold gauge set. When you hook up the gauges you’re testing the pressure on the low and high side of the system to determine if a leak exists. If the levels are equal, it’s likely either a refrigerant level or the temp control.

If you’re not able to complete the pressure test, contact one of our professional mechanics and they’ll be happy to diagnose the issue with your A/C for an accurate repair.

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. Issue with my A/C, what is the most likely problem?

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: There is no power and is shaking in overdrive.

The Mass Air Flow sensor (MAF) may be dirty and causing the throttle position sensor to act up. Remove the MAF and clean it with electrical cleaner and then put it back on. Check all the hose clamp connections to...

Q: Car has trouble starting when it's cold

You may have an issue with your battery. Batteries are measured in cold cranking amps which is the amount of amperage the battery can produce at 0 degrees. If the cold cranking amps of your battery are not up to...

Q: A/C-can the air compressor clutch be changed independent from the air compressor

If just the compressor clutch is bad you can replace it by itself. I know this compressor and clutch have a listed price around $1000, and just the clutch alone is around $600. This is for the part only. The...

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...
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 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.