Skip the auto shop - Our mechanics make house calls

Q: Ac compressor turning on and off

asked by on

My truck was blowing cold air and all of a sudden it would blow only cool and then get back to cold and then sometimes it would blow hot but then the next day it would be cold again. And you can hear the Ac compressor kicking on and off back and forth. I tied adding refrigerant. And I add the correct amount cause it was in the green section and it still cuts on and off

My car has 175000 miles.
My car has an automatic transmission.

A: Hello. If the compressor is turning on and ...

Hello. If the compressor is turning on and off fairly quickly then that means that there is still a pressure issue. It can be caused by low refrigerant or high pressure. It can also be caused by a bad A/C pressure switch. Any of these will cause this to occur.

I usually install a set of pressure gauges that will read the high and the low side. If the system is low I add more refrigerant. If the high pressure side it too high then I check and see if the fan is working as it should. If the pressures are fine then there is a pressure switch issue within the system.

If you want to have this repaired, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose the issue with your A/C and help you fix it accordingly.

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: Dome lights and courtesy lights in back seat will not turn on.

Hi there. When multiple objects in a car will not work that are electrical, then there is a loose or broken ground wire to the circuits. Check all of the wiring in the cab to see what could be loose...

Q: Car stalling when turning on the AC.

A stalling vehicle when the AC or Defroster is activate indicates a problem with the compressor. It is either seized/hard to rotate or the AC refrigerant is overcharged preventing the compressor from turning. This will also put increased load on...

Q: PCM

It sounds like the voltage regulator may be overcharging causing it to essentially electrocute the PCM. As you may know, the voltage regulator regulates the voltage in the system by not allowing the alternator to over charge the battery. As...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...