Hello, I have a 2005 STR and it’s climate control has been a nightmare. I have replaced the compressor, DCCV, and the fan, but now the A/C is weak at idle and pretty much non-existing under load. I’m sure it’s not low refrigerant. Has anyone else had this problem?

 

Best way to check is have the gas removed, weighed, and the correct weight put back. Pretty cheap!

If the two weights are close then you have an actual problem worth pursuing - let us know.

 

What were the symptoms before all of this recent work?

The refrigerant level? Don't hobble yourself while troubleshooting. For all you know, most of the refrigerant may have leaked back out quite quickly through some as-yet undiscovered leak point.

I'd suggest pouring a strong cup of coffee and working through this guide step by step:

https://www.jaguarforums.com/forum/s...ol-how-185002/

No assuming parts are good simply because they are new. For example, DCCVs have a high failure rate, so test the new one. And if the old DCCV was drawing too much current, it may have damaged the control module. Details in the guide.

 

So, first, I tried to just refill the freon myself, got cold while I was doing it, then started blowing only hot air, too it to my mechanic, and he put in a new compressor. Obviously, it didn’t work. He then replaced the DCCV, and came to the conclusion that the new-ish compressor was defective, so he also replaced that. Then it would be cold during idle, but when you drive it would slowly heat up. So he ordered a new cooling fan, didn’t do any thing. Now he’s saying he put a manual override in the old fan, still no luck getting ac while driving. Combing through the car however, I have noticed a couple of times that there is a random wire unplugged, I can’t find where it leads to, but it is on the drivers side under my cold air intake. Might be a red herring giving me false hope that this whole situation is cause by something so simple. But I swear I’m going to lose sleep if I don’t find where it leads (i notices it was unplugged after the first compressor, mechanic says he noticed it but doesn’t know where it leads)


(please excuse dirty intake, I’ve only had the car in my garage for 2 weeks out of the two months I’ve had it)

 

Not sure about that plug. It's in the general area of the AC pressure sensor. Here's the location, on the US driver's side near the radiator:

http://jaguarclimatecontrol.com/wp-c...-switch-02.jpg


If that's not it, I don't think that plug has any thing to do with heating or cooling.

Your mechanic does not inspire confidence. Definitely leave the electric fan alone. If the fan had failed, or wasn't receiving a proper command to run, the engine itself would run hot at low vehicle speed. Above 30mph or so, you have PLENTY of cooling ram airflow through the radiator and AC condenser. The engine coolant would stay in the proper heat range, and the AC performance would be good. However, you're saying the AC performance is poor at higher vehicle speeds, which is just the opposite of a fan problem. A bad fan only causes problems at low vehicle speed.

Hopefully your mechanic hasn't charged you for those two compressors, as they obviously didn't fix the problem. Please work through the troubleshooting guide I had linked in my earlier post. Specifically, before doing anything else, please make sure the DCCV is closing properly on both sides. You may have more than one issue at play, but the DCCV is a prime culprit. If stuck open, it could be dumping heat in the cabin and overwhelming a perfectly good AC system. The S-Type heater output is marginal at idle, and increases with higher engine RPM. That might explain why you seem to have adequate AC at low speed, and then performance drops off at higher speeds.

Please keep us posted.

 

I did the DCCV test, air temp coming out the vent before running it at 1500 rpm was 30F, pretty cool at idle, ran it at 1500 rpm and immediately the vent temp rose to about 65F and I heard the compressor click a couple of times within the first 30 seconds. As for the DCCV temp, about 15F hotter than the ambient temp. Which is where it needs to be. Odd results, but now I’m thinking something with the compressor. Either that or one of the many switches in this system. Another thing to note, the vent temp immediately creeps down when I let off the throttle. Don’t really know where to go from here, I’ll look in to some tests for the switches.

 

Are you talking about the temperature of the air coming out of the vents? If so, and with the control panel set to LO, you should see virtually no increase above ambient. Make sure the AC switch is set to OFF, so you're not getting any cooling effect. For the moment, I'm not testing the AC portion of the system. I'm just making sure the DCCV is properly closed on both sides when commanded. The 15F increase you've described is way too much.

The other symptoms are a little odd, too. My hunch on the temperature change with RPM is based on the heater dumping hot air into the ductwork. As previously mentioned, the S-Type heater is marginal at idle, so that may be part of the equation.

The initial 30F air from the vents is too cold, strange as that may seem. You need to see a slight margin above freezing, to prevent ice accumulation on the outside of the accumulator. 30F might indicate a problem with the evaporator temperature sensor. But before diving in there, please repeat the DCCV test. I put that first in the troubleshooting guide because a problem there can skew other test results.

The cycling of the compressor may be a normal response if the AC output is briefly too cold, so don't read too much into that for the moment. Concentrate on the one apparent fault for now, the vent air that is 15F warmer than ambient. Have you tried that on a test drive, not just while parked? Remember, panel set to LO and AC switch set to OFF. From what you have described so far, I'm willing to bet you will see an even greater increase above ambient.

I hope this system isn't too frustrating for you. Much of the design is different than other systems out there, so troubleshooting that was applicable to a Chevy or Ford may not apply here.

 

No when said “DCCV” temp I meant the temp of the lines under the hood. They were slightly above ambient, meaning the hot coolant didn’t not get in them to make my AC not “make enough cold”

 

I looked at the compressor while the car is running, from what I can gather, the compressor kicks off when the rpms go above 1500 or so. Again, I can’t really tell because I can’t really see in to the engine that well, could it be the ac pressure transducer causing this? That’s where my mind is heading right now, it doesn’t seems to The the DCCV because the DCCV lines remain the proper temp through the test, yet I still get warm, dare I say hot, air under load

 

Ok, so I took the remote climate control modual out. I have the Navi so it’s the one under the dash, I heard you can open it to see if it’s shorted or something of the nature, I currently can’t forgive out how to open it and I don’t want to break it.

 

Now I'm not trying to bust your butt, but I'm still not convinced your DCCV is closing properly. You now mention you have "warm" or "hot" air from the vents. Please define hot. What is the ambient temperature and what is your duct reading? Is the outlet temp warmer than the exterior air? If so, that can only be caused by heat being transferred via the heater core. Remember, the heater output is marginal at idle. It could very well be your AC system can adequately cool the cabin at idle when the heater isn't dumping too much heat into the ducts. Drive at freeway speed and the heater output increases dramatically, and duct temperature climbs.

For the most accurate troubleshooting, make sure the AC button is switched off and the temperature selection is toggled down to LO. Under these conditions, the air at the dash vents should be essentially the same temperature as exterior air. No heating and no cooling. Just exterior air passing through the ducts and nothing trying to warm or cool it. I just got back from a drive and tried this myself. AC off, temp selection to LO, and after about 10 minutes for temperatures to equalize, I showed 80F duct temperature, same as the exterior reading on the control panel. When I wrote the troubleshooting guide, I recorded 72F duct temp on a 69F day, so I'd say a difference of a few degrees is the most you want to see.

So please try that test and report back. The other test (recording heater line temps under the hood), you've already tried. When I tried it, the max difference I had was 5F. You recorded 15F. I can't say which number is good, but there are a lot of variables with that test. The less difference the better, so I'm a little concerned about 15F. I gave some very specific instructions, such as cold engine, hood open, warm up at idle only, followed by 2 mins at 1500 RPM, etc. If you did something differently, you may get a different reading that is inconclusive. But if you measure the dash temp on a test drive, you should know for sure. Drive for at least 20 minutes to make sure the hot coolant has a chance to sneak past the DCCV if it isn't closing properly.

Allow me to repeat myself that I'm not trying to argue with you or bust your butt. I just want to make sure all testing is done properly. I put a lot of work into that guide, based on ideas suggested by forum members. Mostly I organized the info into one thread and put it in a symptom-based format that you can work through from start to finish. I tried all of the tests myself, and tweaked them a little bit as needed for simplicity.

I wouldn't worry about the compressor cycling right now. As previously mentioned, that may be a normal reaction to some input, such as the evaporator temperature sensor. For now, use manual mode (LO displayed at the control panel) to bypass most of the automatic controls. Not sure if you're using auto or manual right now, but manual mode is a huge boon for troubleshooting.

I'm still wondering about the 30F duct reading you're getting initially. That points towards an inaccurate evaporator temp sensor, letting the evaporator getting too cold. Ice will build up, and although nice cold ice sounds good, it interferes with normal heat transfer and causes inadequate cooling. If you're getting a large puddle of water collecting under the car after shutdown, that's also indicative of excessive ice formation. A little bit is normal, but a large amount is a problem. How much is too much? A ballpark guess is a puddle larger than a foot diameter.

But before diving in with this sensor (or anything else), please report your results after a test drive with LO selected and AC off. I want to know numbers for the "hot" you reported.

 

I may have to break out the forum's tranquilizer dart gun. I have moderator permission to use it. Trust me, it's for your own good. You'll only feel a quick sting, and then you will slip into a blissful peace as if inside an Eagle's song. (I'm thinking Peaceful Easy Feeling or Take It Easy, not Life in the Fast Lane or Hotel California.)

Some disassembly details can be see partway down on this page:

https://jaguarclimatecontrol.com/repair-and-upgrade/


However, before delving too deeply, please try the dash vent temperature test I've suggested in my previous post. We need some numbers to quantify the "hot" air you've mentioned. If the temperature is the same as ambient, your control module is fine. It's commanding the DCCV to fully close on both sides, and the DCCV is responding properly. If that is the case, there's no need to disassemble the control module.

 

I got mine open easily.

I was lucky in that I could see a burnt out PCB trace. Others have just had a semiconductor part that was damaged - and you can't tell those by looking.

There are multiple postings with pictures if you want to see, but of course the latter kind look fine.

However, doing the tests you've had posts about reveal the failed module.

 

Whew, I got it open, didn’t think I’d get this far. There is some burning in the back, but I’m not a computer guy so again, I don’t know what I’m looking at. I don’t know if this would be enough to throw my climate control out of wack, but here’s a picture of the burned portion.

 

Your damaged board looks exactly like the picture here:


https://jaguarclimatecontrol.com/new...al-photo-here/


The orientation of the two pictures is different, that's all.

It's time to send your module off for repair and upgrade:


https://jaguarclimatecontrol.com/contact-us/


Glad we were able to stop you from trying a third compressor...

One last caveat: You've found one problem. There may be more than that affecting the operation of the climate control system. If so, don't panic. Fix the known fault, check the operation, and continue troubleshooting from there if needed.

 

Yep, gonna send it off soon, finally gonna be able to sleep know I , at least, found one of the pieces of the puzzle

 

Well, there's still that loose connector floating around out there in the engine bay....ijs

 

What do you mean? I just had the board fixed and under normal driving, the drivers side is cold, passenger is ambient temp. With driving a little hard, the drivers side is ambient and passenger side is hot. Is my new DCCV faulty?

 

With much trepidation, I must ask how was the board repaired so quickly? With a jumper.across the burned section?

https://jaguarclimatecontrol.com/new...t-to-see-this/


Your present DCCV may have burned out the board again. It's a huge design flaw that a bad DCCV can draw enough current to damage the circuit board long before the fuse blows.

Please, please, please have that outfit repair your control module. The repair includes overload protection to prevent a reoccurance. Most likely your DCCV is also bad, so plan to replace that, too. (if you try to tell us it must be good because it is new, I shall taunt you with terrible squinty looks)

 

Just took it to my mechanic, the compressor was making a loud screech when it was kicking in. On top of that, my cooling fan isn’t kicking in