[Jroncobra]

2001 Mustang V6 AC compressor does not actuate. I've read ~200 threads with some historical relevance to this problem, but still no definite answer. High and low pressure is OK. Low pressure switch replaced, no change. Shorting the low pressure switch does not actuate compressor. Compressor works when hooked up to battery, but no power to the compressor from the compressor plug. Some replies state to check the ground and relay. But what ground? And no good description of the relay or its location was found. I haven't tried the battery disconnect for only one thread tried it and it didn't work for them. Any other ideas?

 

[wmburns]

Check fuse F1.2, F2.2, F2.24, and F2.34.
F1=BJB=battery junction box (engine bay)
F2=CJB=central junction box (driver's kick panel)

The CCRM is located in the front right hand fender well. Remove the tire and plastic liner to get access.

Test CCRM pin 12 (RD) for +12 volts (key on).

Test CCRM pin 21 (DG/OG) for +12 volts.

Inject +12 volts to CCRM pin 23 BK/YE, does the AC clutch engage?

Ground CCRM pin 22 (PK/YE) does the CCRM relay click and/or the AC clutch pull in?

The results above will narrow down the issue.

Please review diagram 54-3

 

[Jroncobra]

2001 Mustang AC clutch response

Thanks. It's my daughter's car and she'll visit this weekend, again, so I'll try those inspections. My son has my 96 cobra and it's still going strong.

 

[rmedrano]

I have been having the same problem as above. Tried everything mentioned and still no A/C.

a/c clutch is not engaging and cant figure out the problem. HELP!

 

[wmburns]

Tried everything? Need to post the results of the tests above. Otherwise, not possible to help.

 

[rmedrano]

-Checked the fuses and all of them are good.
-looked into the CCRM and test power to pin 12/21--GOOD
-Grounded pin 22 and nothing happened

Did not Inject +12 volts to CCRM pin 23---Not sure how I would do that.

Could it be the panel switch inside the car. (ON/OFF--switch)???

 

[wmburns]

How to inject +12 volts to a pin. Get a piece of scrap wire. Attach one end to the Positive battery terminal. Connect the other end to the pin to which power is to be applied. If you are really worried about burning something up, install an in-line fuse.

The +12 volt test is necessary to PROVE that the compressor coil is good.

Once the compressor coil is known to work, then if it does not "click" in when CCRM pin 22 is grounded with the key on, then the CCRM is bad (assuming that all of the other tests have been performed in order).

In answer to your other question, did you review the attached wiring diagram?

 

[rmedrano]

I injected +12 volts (from Battery terminal) directly to the compressor and the clutch engaged with no problems and started blowing cold air.

The only thing I can make out of all this, is that there is not enough voltage coming from the original plug (CCRM?) to the A/C compressor.

Does that mean the CCRM is bad?

Sorry about the delay between postings.

 

[wmburns]

Note, the test to inject +12 volts to CCRM pin 23 is designed to test the AC clutch and wiring. By injecting directly to the AC clutch, you have proved that the clutch works. This does not prove the wiring between the CCRM and the clutch.

IMO, it's rare for wiring to go bad unless there is evidence of water/rodent/colision damage.

However, since you seem to need more convincing, test the low pressure cut off switch VT wire. Should have +12 volts with the key on and AC on.

Turn the AC mode control switch off. Verify that the 12 volts goes away.

Now confirm +12 volts on the Low pressure switch DB/YE wire. This will prove the low pressure switch is working.

Finally go to the High pressure switch and confirm +12 volts at the DG/OG wire (key on, AC on). This will prove the high pressure switch is working.

 

[2001GTConv]

Check fuse F1.2, F2.2, F2.24, and F2.34.
F1=BJB=battery junction box (engine bay)
F2=CJB=central junction box (driver's kick panel)

The CCRM is located in the front right hand fender well. Remove the tire and plastic liner to get access.

Test CCRM pin 12 (RD) for +12 volts (key on).

Test CCRM pin 21 (DG/OG) for +12 volts.

Inject +12 volts to CCRM pin 23 BK/YE, does the AC clutch engage?

Ground CCRM pin 22 (PK/YE) does the CCRM relay click and/or the AC clutch pull in?

The results above will narrow down the issue.

Please review diagram 54-3

This thread has been very helpful, thanks!

2001 GT, system never was touched since new. When I was driving, the air became warm and I recycled the switch off then on...that worked a couple times but only for a minute or so. I thought I was riding the low pressure switch since I had never added freon to the car ever. The low side pressure was around 25 psi and I charged it back up to 45. The car blew cold for a few days then once again it started blowing warming.

My A/C works great when 12v is applied to the compressor clutch...cold air and normal pressures. The low side pressure is still 45 psi

On my car I'm getting 12v with the key at RUN on pin 12 when the connector is attached to the CCRM.

I do have 12v on pin 21.

I injected 12v to pin 23 and heard a loud clunk.

jumping the low pressure switch does not engage the clutch.

I do get 12v at the high pressure switch.

All fuses have been checked.

Selecting A/C on the dashboard sends 12v to the low pressure switch and 0v when not selected.

I didn't test the low pressure switch since jumping the switch yielding no change.

Any ideas?

Also, it seems like there are a lot of different part numbers for the CCRM's. Mine is B 1R3F-12B581-AA Service P/N 1R3F-12B577-AA. Are they all the same?

Thanks

 

[wmburns]

There are different CCRM's for the model engine and engine (V6 or V8). I'm going to assume this is a 2001 V6.

Confirm there is +12 volts on CCRM pin 12 (RD) with the key on. If not, fuse F2.2 is bad.

Ground CCRM pin 22 (PK/YE) with the key on. The AC clutch should engage. If not, the CCRM is bad based on the other test results.

Recommend getting a re-man unit from your local auto parts store.

Cardone Remanufactured 73-70012 - Body Control Computer | O'Reilly Auto Parts

 

[BMackKC]

I have the same problem on 2000 V6. CCRM part code is "Y." Mechanic diagnosed faulty CCRM. Replaced with a salvage unit, still no AC and condenser fan runs even with ignition off and engine cold. Put the old one back in.

My son's car...he's responsible for the maintenance costs, so going no further until he has the money in a couple of weeks.

We're in the middle of a huge heat wave, 108 tomorrow in KC area. Can I jerry-rig this by putting 12v directly to the compressor? I would probably need to tie it to an engine-on circuit, yes?

Or is this a REALLY bad idea?

 

[2001GTConv]

It's a 2001 GT...4.6l...pin 12 has 12v

There are different CCRM's for the model engine and engine (V6 or V8). I'm going to assume this is a 2001 V6.

Confirm there is +12 volts on CCRM pin 12 (RD) with the key on. If not, fuse F2.2 is bad.

Ground CCRM pin 22 (PK/YE) with the key on. The AC clutch should engage. If not, the CCRM is bad based on the other test results.

Recommend getting a re-man unit from your local auto parts store.

Cardone Remanufactured 73-70012 - Body Control Computer | O'Reilly Auto Parts

 

[DasCMXI]

I know this is an old thread but I need HELP! I have NO power to CCRM pin12 with key on. Fuse F2.2 is good. I do have power to CCRM pin 21. No clutch engagement injecting 12v into pin 23 and no clutch engagement grounding pin 22. I checked the resistance at the clutch coil and got 3.6 ohms. Any help what to do next would be appreciated. Trying to help my son fix his '03 Mustang 3.8.

 

[wmburns]

I know this is an old thread but I need HELP! I have NO power to CCRM pin12 with key on. Fuse F2.2 is good. I do have power to CCRM pin 21. No clutch engagement injecting 12v into pin 23 and no clutch engagement grounding pin 22. I checked the resistance at the clutch coil and got 3.6 ohms. Any help what to do next would be appreciated. Trying to help my son fix his '03 Mustang 3.8.

Have you CONFIRMED key on power INTO fuse F2.2?

Have you verified the grounds around the radiator core support? There are several on the right and left side. It would also be wise the measure the Ohm resistance from the CCRM black wires back to battery negative. Should be very low. Do this test with the battery positive disconnected.

Has this car been in a wreck? I have to say to go back and check your work. Because if there's key on power out of fuse F2.2 and there's no power at CCRM pin #12 (RD), then a wiring harness fault is the next logical theory. If the base assumptions/tests are wrong, then a long wild goose chase maybe in your future.

Also if injecting +12 volts into CCRM pin #23 (BK/YE) does not cause the AC clutch to engage then:

• The AC clutch is bad
• There's a wiring fault beteen the CCRM and the AC clutch
• The CCRM ground is bad/weak.
• You don't have the correct pin numbering.
• trying to apply trouble shooting steps to a different model year or engine than what these were originally written for. There are differences between the V6 and V8's. As well as differences across the model years.

 

[Ali alghazwi]

Hi everyone,
I don’t know if any body will answer my my question 😅

I have mustang 2002 V8 , a/c not working ,
I have checked fuses and everything thing ok , even I try to inject 12v to ccrm pin 23 and ground to pin 22 the compressor run and every thing ok , but still it is not working ?!!

 

[90lxwhite]

I’d bet the farm that y’all have a leak in the system and no r134a is left. When that happened the compressor probably crapped out. Is the bottom (or anywhere else) of the compressor greasy?
Filling it up won’t help.

 

[Ali alghazwi]

There is no leak from the compressor,

 

[Ali alghazwi]

I inject 12v in ccrm pin 23 and the compressor working very well.