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AC making noise like power steering

ldj1002 on Sun February 27, 2011 8:02 PM User is offline

Year: 2002
Make: ford
Model: crown victoria
Refrigerant Type: 134
Country of Origin: United States

Wife pulled in driveway and car making noise like power steering when fluid is low. Checked fluid, it is full. Turn wheels noise doesn't change. I decide not PS so I start checking where noise coming from. Hummmm, sounds like coming from AC and compressor is running. I go in car to turn ac off to see if sound goes away. AC won't turn off. I unplug plug from compressor and noise stops. Question, what would make the compressor make that whining sound like PS when fluid is low and why won't the compressor shut down with controls in car?

Went out today to double check everything and it all acts the same. It is 75* humidity 62% I plug in compressor and in just a minute or so the line from compressor to and including dryer is frosted over. It that normal? I didn't notice or pay attention to it frosting the other day. I have not put gauges on.


NickD on Mon February 28, 2011 9:14 AM User is offline

Sounds like this can have shorted contacts.



Clutch relay, the rest of it? Can try hand turning the hub, should be easy, do I have to say this with the ignition keys in your pocket? Assume you have belt squeal, that can be any number of reasons, just remove the belt and check each sheave for smooth operation and play. Even a corroded tensioner pulley that no longer operates smooth.

If the clutch relay is okay, can be what's driving it is not.

ldj1002 on Mon February 28, 2011 9:36 AM User is offline

This morning I took belt off and clutch pulley turns smooth. Did not turn compressor with plug in. Also removed pressure switch plug and compressor clutch still energized. The relay in photo, where do I find it.
The noise I hear is a groan or???, NOT a sequel or chirp. The noise does get louder with rpm.
Are you saying my noise is not from compressor, that it has to be from pulleys, belt or some where else even though no noise when compressor not turning?

NickD on Mon February 28, 2011 12:02 PM User is offline

Not there to hear it, but sounds like your compressor is headed south with the sound, did you try to hand turn it? Any slight binds is an indication of trouble. Perhaps someone else can help with the location of that relay.

bohica2xo on Tue March 01, 2011 3:17 AM User is offline

Clutch relay is located in "Relay Center Box 1" located in the left side of the engine compartment.

Sounds like a relay welded shut. The compressor will be complaining loudly if it is not cycling. Replace the relay, and check that the fan operates on both high & low speeds.

Compressor may make less noise if everything is working properly. The fans & HPCO are controlled by the PCM. If the relay is turning on the compressor without a signal from the PCM, the fans are not receiving a turn on command from the PCM.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

ldj1002 on Tue March 01, 2011 10:13 AM User is offline

"Relay Center Box 1" Does that mean it is in the #1 position? If so, I pulled that relay and compressor still runs.
L.D.

I found it on left fender. I removed and ac does not run. I took the reley from rt. fender, the rear defrost relay, and has the same part# and put it there. Ac won't run.

Edited: Tue March 01, 2011 at 11:34 AM by ldj1002

NickD on Tue March 01, 2011 1:12 PM User is offline

Have vehicles with a bunch of the same kind of relays in a box, wouldn't it be nice if they labeled their function. But this is where an alldata.com or shop manual helps.

So you are saying you first pulled the wrong relay then by finding the correct relay, the compressor finally stopped. Then you replaced that relay with one you think is good, but have no means to test it, and it still didn't run?

So is it that relay that is the culprit or is it that your pressures are too low? Can also be problems with the PCM, either firmware of some other sensor thinking your engine is overheated but its not, or you are accelerating and you are not, like a MAP or TBS being defective.

They don't make it easy.

bohica2xo on Wed March 02, 2011 3:45 AM User is offline

Quote
Originally posted by: ldj1002
"Relay Center Box 1" Does that mean it is in the #1 position? If so, I pulled that relay and compressor still runs.

L.D.



I found it on left fender. I removed and ac does not run. I took the reley from rt. fender, the rear defrost relay, and has the same part# and put it there. Ac won't run.

Time for pressure readings. If the system is low on refrigerant, it will not run with a good relay in the socket. With the compressor running regardless of the PCM input - and no fans running, you could have had a high pressure event. The HPCO can't shut the system down with a bad relay. If things go high enough, you can pop the relief valve & dump the charge.

Get a static pressure reading on the system & get back to us.

B.



-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

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