Skip the auto shop - Our mechanics make house calls

What Sensors in the AC Tell the Car If the System Is Working or Not?

ac malfunction sensor

The average car today contains a bewildering range of sensors that feed information to various computers to monitor everything from air intake to emissions and engine timing. Your car’s air conditioning system also contains a couple of sensors that manage operation. However, unlike oxygen sensors, MAP sensors and others on your car, they don’t feed information to the computer. You can’t “pull a code” on an air conditioner malfunction.

Air conditioning components

There are two primary components that manage the operation of your car’s air conditioning system. The first and most important is the AC compressor. This component is responsible for pressurizing the system during operation. It also adjusts based on your input – when you change the temperature in the cabin through the HVAC control panel. The clutch operates the compressor based on your settings (but it doesn’t really “sense” whether the system is working or not).

The second component is the clutch cycling switch. This is a safety switch designed to keep the system off if there is not enough refrigerant for safe operation. It’s also designed to monitor the temperature inside your car’s evaporator core to ensure that they don’t drop low enough to freeze the entire core (which would stop AC operation).

Both of these components play a role in temperature monitoring and control, but neither of them communicates this information to the car’s computer. Diagnosing an automotive air conditioner problem will require a professional diagnosis of the symptoms (blowing hot air, not blowing at all, noise from the compressor, etc.), and then a complete inspection of the entire system coupled with a check of refrigerant levels, often with a special UV dye to detect leaks.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

P0222 OBD-II Trouble Code: Throttle/Pedal Position Switch/Sensor B Circuit Low Input
P0222 code definition Throttle/Pedal Position Switch/Sensor B Circuit Low Input What the P0222 code means The manufacturer specifies a range of acceptable voltage to be produced from the throttle position...
How to Get a Louisiana Driver's Permit
s licensing program. The first step in this program is to obtain...
Veteran and Military Driver Laws and Benefits in Idaho
The state of Idaho offers a number of benefits and perks for those Americans who have either served in an Armed Forces branch in the...


Related questions

Q: A/c pulley bypassed Now it has a knocking sound but doesn't sound internal? timing was done at 180k

Hello there, a variety of faults will cause a knocking noise in the engine. The most common would be a belt tensioner, idler, engine rods, engine bearings, low oil pressure/level, power steering pump, or alternator. With so many possibilities the...

Q: Can I Get Cold Air Without Running the Air Conditioner?

All vehicles produced today are equipped with air conditioning systems. If you do not want the air conditioning on but you would like fresh air to come into the vehicle then all you would have to do is turn the...

Q: My MAZDA 3 2005. The air conditining was getting charged and the man was having trouble saying that the AC wasn't going cold at all.

Check the air conditioner compressor and see if the compressor is making the noise. If the noise is coming from the compressor, then the compressor could be out of oil or there could be something wrong with the compressor internally....