My Car A/C Compressor Will Not Come On

car air conditioner will not come onCan you tell me why the air compression in my car is not coming on?

– A/C compressor not engaging

– 2005 Town & Country.

– The A/C light comes on in the van. I am not able to hear the A/C Compressor engaging when the button is turned on.

– The 15 amp fuse & relay are good in the fuse box under the hood. I checked the relay by using another one in the fuse box.

– This is the first time trying to use it this year. Last year it worked fine.

Thanks for your help,

Hello Mike,

The first thing I would do is check the air conditioning system Freon level and pressure with A/C gauges. If you have a small Freon leak in the system and enough Freon has leaked out the low pressure A/C switch will not allow the compressor to come on.

Sometimes with the new R134A Freon systems just a small amount of Freon added to the system will be enough to allow the compressor to come on. You should then have the system checked for a Freon leak, since it is NOT normal to have to periodically add Freon to the system.

Good video on Freon leak detectors and what they do and how to use

If the Freon level checks out OK and you still have problems I would then test the electric cooling fan motor that is up in front of the radiator.

Good video on checking Freon pressures using a manual gauge

This electric fan is needed for the A/C system and the fan should be ON when the A/C compressor is ON. This fan is controlled by a relay and gets a signal from the A/C control head inside the vehicle and the on board computer.

Unfortunately both suggestions are not very easy to test yourself at home and really should be done by a trained mechanic, unless you know what you are doing. Adding too much Freon to the system can do damage.

Please share this with your friends,

Austin Davis

Posted in: A/C and Heating

3 Comments on "My Car A/C Compressor Will Not Come On"

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  1. Harn says:

    The low pressure switch which is located on the A/C drier on my GMC pickup was the problem with my compressor not coming on. My mechanic used a metal paper clip and by passed the switch and it worked.

  2. Rita says:

    hi i was woundering cause i have a chysler 300m 200o in i put lots of money in ac work now i got a ac compresser also feron in charge no they sayin one of my wires bad because my clucth want kick in went to three difrrent shops

    • Austin says:

      I would need to check it out to be sure, but could be a relay, a switch on the dash control or a bad clutch or the gap on the new compressor is too wide and needs to be adjusted. I would go to a dealership and get a proper diagnosis, then you can have anyone you want do the repair once you know what it is the problem.

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