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The other day, I turned on the air conditioning, just to see if it still worked after winter, and no cold air! (I know - I should run the A/C even in the winter to keep everything lubricated) I did a quick check & discovered that the A/C compressor clutch was not engaging. I did check the appropriate fuse & it was OK.

What are some common things that will cause the clutch to not engage & what are some things that I can check?

Dave
 

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Actually, if you use your defogger in the winter, and I think everyone does, this runs the A/C compressor to help take moisture out of the air, so you don't have to worry about actually using the A/C in the winter.

About your problem, though. First thing I would do is use some jumper wires to manually activate the clutch, thus bypassing all the electronic controls. If it engages, you know the clutch itself is good. Lots of things could cause the clutch to not engage, like a wiring problem or low pressure in the A/C system (this is a safety feature so your compressor won't burn up).
 

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I am having the same problem kind of. I noticed that even with my heat turned just on the floor setting, and all the way low and half way between hot and cold, that the air was still coming out soo hot. i was dying. cause i'm very hot blooded, so any kind of heat makes me die. anyhow, so i turned on the AC and it was hot air coming out of it. I had it on high, on cold, and on MAX AC for like 15 minutes and it did not get cool once. it was hot hot hot. what is wrong? do i need to get a recharge or something? it was working totally fine last summer. i need to get this fixed before summer comes otherwise i will melt in my car. Someone help. thanks! i saw this thread and i didn't want to start another one about the same question. sorry.
 

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Sarah it sounds like your problem might be the blend door which regulates the amount of hot air passing through the heater core vs. cool outside air or air passing through the A/C evaporator. I know it can't be hot outside where you live right now, so even if the A/C were not working, you would at least be able to get air that's as cold as it is outside.
 

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The blend door uses vacuum to open and close, so there could be a vacuum leak or the door could be stuck. I think this was a common problem on Gen 2's, but I have no experience fixing them so I really can't tell you any more. I do think the whole dash may have to come out though.

Found this on MSN Autos, it applies to Gen 2 but it's probably similar for Gen 3's.
QUOTE
An occasional problem on this vehicle is failure of the Blend Door Actuator.The cost to Repair the Blend Door Actuator is $65.00 for parts and $299.00 for labor.[/b]
 

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First you need to determine if the compressor is coming on or not.

To force the compressor on apply twelve volts to the compressor side of the low pressure switch while the car is running.

If this turns on the compressor then either the switch is bad or you are low on freon.

If the compressor clutch does not engage even when powered directly then the clutch coil is bad and needs changed.
 

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Make sure the compressor is engaging with the A/C on. Then check the level of ref. in the system by using a gauge set.

The "jumper wire" on the clutch cycling switch will verify if the compressor works, however, only do this briefly as there may be no/low amounts of ref. and oil in the system and you can damage the compressor.

Get back to us.
 

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Sarah,

Sounds like the temperature blend door is not responding.

Are the position switches working correctly? (panel, floor, Defrost ETC....)

Do you have an aftermarket radio with the Manual Climate Controls?
 

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Discussion Starter #11
Thanks for all the replies so far. Right now it is snowing again, so I won't be doing any testing today!

-qaz- you mentioned that the compressor won't come on if it is too cold - how does the car know if it is too cold? I thought if I had the A/C switch on & the temp. knob set to cold, I should get cold air?!?

SHOZ123 - you said to apply 12V to the compressor side of the low pressure switch while the car is running. Is the switch on the compressor itself? And is the polarity clearly marked? I wasn't able to find anything in the Haynes manual.

Thanks,

Dave
 

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The pressure switch is on the return line near the compressor usually. There is no polarity it just feeds 12V+ though it to the compressor clutch coil. One side should always have 12V+ when the key is on and the compressor should be on. If the pressure is too low it will open and shut off the current to the A/C clutch.

You can also at this point check the resistance of the clutch coil. This will tell you if it is too high or open.
 

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The A/C cycling switch besides measuring the pressure of the A/C system also measures ambient temperature. When the ambient temperature is approx 7-10 deg C (45-50 deg F) the A/C compressor wont engage.

There is no point in running the A/C compressor if its already cold outside, the already cold air can be used directly. So yes you should get cold air but if ambient air is cold enough there is no need to run the compressor.
 

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The A/C low pressure switch is just that, no temperature measuring at all. The A/C compressor will run at cold temps. This is done to a. keep the oil circulating through it periodically and b. to improve the defrosting operation.
 

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I dont want to argue or anything but I'm pretty much quoting the ford service manual. Besides as temperature lowers the pressure of the refrigerent will also drop.
QUOTE
A/C Cycling Switch

The A/C cycling switch is mounted on a Schrader valve fitting on the top of the suction accumulator/drier.

* A valve depressor, located inside the threaded end of the A/C cycling switch, presses in on the Schrader valve stem.

* This allows the suction pressure inside the suction accumulator/drier to control the A/C cycling switch operation.

* The electrical switch contacts will open when the suction pressure drops to 152-193 kPa (22-28 psi).

* The contacts will close when the suction pressure increases to 276-324 kPa (40-47 psi).

* Ambient temperature below approximately 7-10°C (45-50°F), during cold weather seasons, prevents the A/C cycling switch contacts from closing.

* This is due to the pressure/temperature relationship of the refrigerant and the requirement of the system pressure to reach 276-324 kPa (40-47 psi) to close the A/C cycling switch contacts.

* These contacts control the electrical circuit to the A/C clutch.

* When the A/C cycling switch contacts close, the signal to energize the A/C clutch is sent to the constant control relay module (CCRM).

* The CCRM then supplies the voltage to energize the A/C clutch for A/C compressor operation.

* When the A/C cycling switch contacts open, the CCRM opens the A/C clutch electrical circuit to de-energize the A/C clutch and A/C compressor operation stops.

* The A/C cycling switch will control the A/C evaporator core pressure at a point where the plate/fin surface temperature will be maintained slightly above freezing.

* This prevents A/C evaporator core icing and the blockage of airflow.[/b]
 

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Yep. My 89 Sable has a ambient temp sensor. Last winter I thought my AC was broken. But, then summer came along and it worked fine. The AC only works in defrost mode when it's cold outside.
 

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I must ask your apologies. This is indeed true with the manual A/C. But with the EATC the A/C compressor will come on regardless of outside temperature. The EATC is all I have experienced on my Taurii.
 
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