Skip the auto shop - Our mechanics make house calls

Q: Air conditioning clutch is not engaging unless I bypass the relay.

asked by on

Before I started having this issue my A/C would take a while to get cold and in stop and go traffic would barely keep it cool. When driving on the highway 60+ mph it cooled much faster. I have cleaned the condenser with coil cleaner and had the A/C serviced. The lines have been vacuumed and also have been recharged. The pressure gauges read 210-225 on high side and 40-45 on the low side. The vehicle has rear A/C and calls for 2 1/4 lbs of r134a so I charged it with 36oz = 2 1/4 lbs. A few weeks ago I noticed the A/C clutch not engaging so I bypassed the relay and it turned right on, when I removed the bypass and replaced the relay it stayed engaged as long as car was running. If I turn the car off it would need to bypassed again to engage. All the pressure levels are maintaining so there are no leaks and it's not low on freon. My guess is the A/C pressure switch but I thought I would ask.

My car has 70000 miles.
My car has an automatic transmission.

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: Heater was not blowing warm air and then the engine overheated.

The heater not working in some cases may be related to the overheating problem you are also having. This may be due to a faulty heater blower motor or potentially a bad heater core. As you may know, the heater...

Q: Multiple problems with the car I just purchased

Hi there. I am so sorry that this has happened to you. The Check Engine Light bulb needs to be replaced so that you know when the system sees a problem; you didn't know that you would fail the emissions...

Q: Loud noise coming from air conditioning

After washing an engine it is common for water to cause some problems. Most of the time the water will end up being forced out and the noise will go away. In some cases though the water will damage the...

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...
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...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...