Starting a new thread for my AC repair journey. A few weeks ago I was driving on the highway with the Air Conditioning running perfectly, until it just suddenly stopped blowing cold air. Here were my symptoms:

-AC button is lit, heat works fine, blower fans are operative and I can hear blend doors operative. All climate functions work so I don't think the Climate Control Module is the issue.
-AC compressor clutch does NOT engage at all or make a solenoid click sound.
-Condenser fan does not turn when engine is cold and AC button pressed.
-no fuses blown

My troubleshooting process:
1. Checked R134a refrigerant static pressure and measured ~100psi so there is plenty refrigerant in the system. No leaks visible under UV light (PAG oil has UV dye in it, even from the factory).
2. Checked SDD- no DTCs shown for Climate Control Module
3. Jumper wire on the Refrigerant Pressure Switch (underneath the driver's side headlight behind the bumper) to eliminate the pressure switch as a problem. If refrigerant pressure is too low, this would have thrown a DTC and will not let the compressor clutch engage to avoid damage.
4. Next, I followed the checklist for the DPS valve on the rear of the compressor as it is a known failure point. All my symptoms indicated a bad DPS valve per the Jaguar TSB (readily available on these forums). I replaced the DPS valve and the AC still did not work. Onto the next...
5. FINALLY... what I should have done before step 4- I measured the voltage on the AC compressor wiring harness going to the clutch. Multimeter indicates 14v with the AC switched on, and no voltage with the switch off. So the AC compressor clutch is receiving signal, but isn't activating.

Long story short, I've narrowed down at least one of my problems being that the AC compressor clutch isn't functioning. So now I either have to replace the compressor or the clutch itself. I'm leaning towards replacing the entire compressor as an assembly, but finding the correct part number may be difficult. Jaguar used three different compressor configurations throughout the model range. My compressor is a Sanden PXC16. It uses the wide-barrel DPS valve and is equipped with the electromagnetic clutch.

I will continue to report back as I tackle this issue. It's getting hot here, and having a daily driver without air conditioning is demoralizing.

 

Update: I ordered a reman compressor, RYC part# IG573 which is a remanufactured PXC16 compressor. Will update next week when I get around to installing it.

 

I think you were wise to replace the entire AC compressor. That's what I did after messing around with changing the DPS at first and finding there are 2 different DPS valves and of course I had ordered the wrong one.

I would replace the filter/dryer sock just because it's so cheap at around $15 or so. It's a good work practice and the compressor people usually require that for their warranty to apply. They also recommend flushing but I don't do that unless something has come apart and contaminated the system.
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I have a 2011 XJL 5.0 Supercharged. I just replaced my compressor this past weekend. I took it to the local shop to empty the system. Not much help on Youtube for this kind of install. One thing that did help was seeing the the oil cooler(I think thats what it is) needs to be removed and access comes from inside the fender well. I actually removed the compressor from underneath the car but I think it can go top or bottom. Took me me about 5 hours but I'm slow and I take my time. Had it recharged today and it is as good as new.
Good luck.

 

This is my recent thread and yes the first time I did remove the transmission oil cooler and poked a hole in one of the hoses so I got to do it again!
Here is my thread with a few pictures.
AC Compressor Removal

Since I have done it twice I learned a few things and the second time I moved the transmission cooler and hoses and held them back out of the way with wire ties. I did not disconnect them. I see zero possibility of removing the AC compressor from the top? Even coming out the bottom there is very little room.

Did you see my post on the filter/dryer and where to get it much cheaper than Jaguar? Hope you did replace it when the compressor was replaced?
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I did not remove the transmission oil cooler either when I removed the compressor. I just unbolted it from its plastic mount that bolts to the subframe, and wrangled it out of the way. The two 13mm hex nuts that hold the hard lines to the compressor were very difficult to access this way, but I managed it as I didn’t want to bother with removing the cooler.

There is definitely no room to remove the AC compressor from the top of the engine bay. I simply drove the car up on ramps and didn’t need to remove the wheel. That top bolt that holds the compressor to the engine block is very difficult to access and took a combination of socket extensions and a U-joint to remove.

I am replacing the desiccant bag with part # Omega 37-13686. I have not reinstalled my new reman compressor yet, but will report back this weekend.

 

Good work. What were your symptoms that caused you to diagnose the compressor as the issue?

 

My issue was a bit different. When I would slow down or come to a stop, the air would diminish. It was never hot but it was not as cold as it should be. I took it to an AAMCO and they determined that the compressor was leaking. They filled it up using dye and when the system was full, the air was cold. As the compressor leaked, the air was just not work properly. We came to the conclusion that the compressor had not started to shed parts in the system and the system seemed clear. With the amount they want to charge for a full system replacement, it was worth just trying the compressor. So far, so good.
Good Luck!

 

Update here. The R&Y reman compressor arrived but the box was trashed and the pulley did not have a clutch like I thought it did in the listing. So I returned it and I bought another remanufactured PXC16 1690P compressor (with clutch) that I bought from a parts house on eBay for $300. I swapped over my brand new DPS valve (just to have a guaranteed new part in there), bolted it to the car, then vacuumed the system down to about 29inHg. It held vacuum for 20 minutes so I charged with the prescribed 1lb 8.5 +/- 1.0lb of R134a. Works great!

Couple of tips:
-I will charge refrigerant only by WEIGHT from now on. As I was filling the system, the pressure gauges showed readings inconsistent with a temp/pressure chart for R134a would suggest. Charging by weight is the proper method to avoid a whole host of problems I won’t get into here.
-Don’t worry if the compressor doesn’t turn on immediately when you start charging the refrigerant. Static pressure in the system has to reach around 80psi or so first before the compressor clutch will be allowed to engage.
-I did replace the dryer desiccant bag, which is as you should anytime the system is open. Water reacts with the refrigerant and oil to form an acid that deteriorates the sensitive AC components.
-I unbolted the oil cooler from its plastic mount but the surprisingly large bolts that attach the mount to the subframe had corroded and spun in their mountings. This made removing and installing the compressor more difficult. If I did this job again would just remove the mount; I would not drain the cooler.
-I did this job on ramps without removing any wheels. Removing the wheel and subjecting yourself to the liability of working under a jack stand isn’t worth it in my opinion, ramps are safer.

 

Good to hear Jaaag Drivah. I think the problem with the first compressor is the part number. The IH537 from RYC has the clutch but the IG573 does not.
A couple of things. Going thru the fender well and removiing the oil cooler gave me access to the bolts to the compressor. If you do this from top or bottom to access the bolts, that would seem impossible. bag?
Also, what were the steps to replace the desiccant bag?

 

Yea those large bolts holding down the plastic base for the transmission oil cooler are facing straight down with no drain holes. I live in a no salt dry area and those two bolts were rusted as Jaaag_drivah found out. Glad to hear you can work around it. I got both those bolts loose and they are now well coated in Anti-seize. When I had to go back in the second time they came apart fine.
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Super easy to change the drier with the system discharged. Remove the air guide/splash panel under the radiator. The desiccant bag is on the passenger side (USDM cars) of the condenser inside the receiver/dryer area above a plastic internal hex plug. Remove the hex plug carefully as it is fragile. There is a filter attached to the plug that you should clean and blow out. Your existing desiccant bag may be swollen with moisture, dirt and need some encouragement with pliers to remove.

 

Thanks Jaaag,
I probably should have done that when I had the system empty. I thought it was more involved than that. Seems very simple.

 

Yes it should be changed and I found the bag much cheaper than anywhere else too.
With pictures and part numbers here is my replacement thread. Note that the filter can be cleaned but I wish I had replaced it when I did mine. I found a surprising amount of powdered metal in the chamber/fine screen.
AC Dryer Bag Replacement
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Update- my reman AC compressor is having issues again. Same issue I initially came across- the compressor clutch won't engage. I haven't done any troubleshooting yet but the last time I did, the clutch was receiving a 12v signal. I suspect that water has damaged either the wiring within the clutch or worn down the actual clutch plates because I don't have the undershield tray on my car and it stopped working a few days after a major rain storm.

I'm really not looking to pulling that AC compressor off the car for the THIRD time.

 

I did some diagnostic work today. A few notes:

• I am still receiving ~14v running signal to the compressor clutch.
• It is not a clutch plate wear issue because the clutch plate does not move when engaged, i.e. the coil may be faulty as it is not even attempting to engage.
• The AC compressor clutch is grounded through the engine block and I'm not experiencing any other ground-fault related problems.
• There is a small oil leak from the front seal of the reman compressor. Very disappointing but thankfully the seller will respect the warranty. However, I am inclined to think the refrigerant charge is still high enough because the module is still sending 14v to the clutch. If enough refrigerant had leaked, the pressure switch would trip and not allow the compressor to engage.
• Relay R1 sends full battery voltage from the battery directly to the clutch. R1 is a standard 12v 70A relay. I suppose I can check to see if any of the cable connections are resulting in high circuit resistance and thus excessive heat.

 

Overdue update on this thread. The main issue of my AC not engaging was mainly a clutch plate wear issue. I will run through the diagnostic process again for the benefit of the readers.

The symptom of "my AC isn't blowing cold" can be shared among a variety of different HVAC system pathologies such as low refrigerant due to a leak, bad DPS valve (a known issue on these cars), burnt AC clutch coil, worn AC clutch plates, wiring issues, burnt solder traces in the HVAC module, and other maladies. Air conditioning theory is poorly understood by the majority of hobbyists and even mechanics, and you need to have a strategic diagnostic process for this system or you will lose your shirt financially.

Symptom: AC doesn't work.
Does AC button light e.g. does the HVAC control module engage other AC activities such as moving blend doors and starting the fans? >Yes
Is the AC compressor clutch fuse blown? >No
Does the AC compressor clutch relay engage? >Yes
I can now eliminate refrigerant charge level as an issue. If the refrigerant was low, the AC pressure switch would be tripped and disallow the AC relay to operate the clutch.
Does AC compressor clutch have power at the compressor connector in the engine bay? (check your wiring diagrams for the pinout) >Yes
Does the AC compressor spin when the clutch is engaged? >NO
At this point you can ignore testing the DPS valve for now. That doesn't 100% mean the DPS valve is GOOD, but the fact that the clutch is not engaging will mask any DPS valve symptoms so we need to solve that issue first.
I'm now asking myself WHY does the car send power to the clutch without successful engagement?
Does the AC clutch coil itself show electrical continuity and resistance? (Check with multimeter)>Yes
At this point my AC clutch coil isn't burnt out or shorted. That doesn't mean it is strong enough to pull the clutch forward, but let's test that.
What is my AC clutch air gap clearance? Does it change when 12v is applied to the clutch? >Too much clearance (model-specific but should usually be at or below 0.5mm).

So your clutch air gap is too large and the clutch plates won't grab, thus your AC compressor is not actually engaging even though the clutch coil attempts to engage the friction plates. At this point you can pull the front of the clutch plate off (only one bolt and no special tools required) and remove shims, check your clearances again and retorque the spindle nut. No evacuation and vac-down required. If pulling a shim doesn't fix the issue, your clutch could be worn below spec and require a tool to pull off the compressor hub and replace. That's a job that can also be done with the compressor installed on the car.

In my case the front oil seal was leaking, so I needed to pull the compressor off the car anyways. Now it's back together, recharged and running well.

 

I no longer work on or change any shims on AC clutches. With all the work needed (just like the DPS) I now just go for a AC compressor change out. I also like you went in multiple times fixing what I thought were specific issues only to have more AC problems. I finally just replaced the entire compressor and a year later all is still well.
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One thing is for sure, I won't be buying reman AC compressors anymore. The $2-300 savings is not worth the hassle.

 

New only then? I have gone back and forth on that myself. I did stay with the Sanden brand as that's OEM.
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