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Great information in this post. After reading through this my head is swimming with great info. I am having an issue that you may have answered in this post (probably) but my mind is not absorbing. I am getting cool air on the passenger side in all modes of operation but, the drivers side only seems to blow warm air. Where would be the most likely place to start?
For testing the DCCV to make sure it closes properly, forum member Brutal reports excellent results pinching off the large heater return hose using a pair of Vise-Grips. This blocks the coolant flow through both halves of the heater core for troubleshooting. Excellent advice, but the only change I'd suggest is to use a pair of smooth-jawed pliers to help avoid damage to the hose. Here's one type, other styles are avilable:
For testing the DCCV to make sure it closes properly, forum member Brutal reports excellent results pinching off the large heater return hose using a pair of Vise-Grips. This blocks the coolant flow through both halves of the heater core for troubleshooting. Excellent advice, but the only change I'd suggest is to use a pair of smooth-jawed pliers to help avoid damage to the hose. Here's one type, other styles are avilable:
I am going to make some coffee! This looks like a great read. I’m sure that by my “new member intro,” you could tell that I am still a “but, why?” Kid 😁. As such, I am thanking you advance for the verbosity and thoroughness of this post!
I am going to make some coffee! This looks like a great read. I’m sure that by my “new member intro,” you could tell that I am still a “but, why?” Kid 😁. As such, I am thanking you advance for the verbosity and thoroughness of this post!
Forum member Gerard Radimaker has suggested an edit for the DCCV checks in post #2, which I am happy to include. If your troubleshooting leads you to suspect the DCCV, I've already included steps to check the DCCV connector for proper power and ground to operate each side of the valve. On his 2005 model, Gerard found a broken wire at an intermediate connector, as detailed in the following thread, well worth the read:
This appears to be connector CP1, seen in figure 06.1 of the wiring diagrams. This is a ten pin connector, and is hidden inboard of the washer fluid tank. The best access is from below, by removing the nose pan under the front bumper. He thinks the wire harness may have been accidentally stretched during a previous repair of the bumper, but for all we know there may not have been enough slack from the factory.
Image courtesy of Gerard Radimaker
Image courtesy of Gerard Radimaker
Many thanks to Gerard for the pictures and permission to use them.
I encountered a little troubleshooting snafu recently with the AC, and wanted to share what I had found. During a recent heat wave (115F!), the radiator cooling fan failed on my car. Gory details here if interested:
Actually, that's not a conditional statement. Details are at the link even if you're NOT interested, but already I've digressed.
The primary symptom of the fan failure? No AC. My beloved wife (only got one, in case I have to be specific) had taken the car to the store, maybe only a half mile or so away. Two very short trips separated by at least 30 minutes, so the engine never had a chance to overheat even with the dead fan. Had she driven further, the fault would have reared its ugly head, but not in this case. However, she did mention the AC wasn't working at all. Initially I thought it was a combination of heat-soak and such short driving time, but sure enough, there was no cooling at all when I tested it in the driveway.
I followed my handy dandy troubleshooting guide and went to post #5 for no cooling. Time to confess, I actually skipped around a bit, briefly looking at several things and I tripped myself up. I sat in the driver's seat, started the engine, selected manual LO for cooling, and then looked under the hood. The AC compressor clutch was not engaged. That's a bingo! I had found the problem, or so I convinced myself. Turns out the compressor clutch did indeed engage normally when I first started the engine. But after the 20 seconds or so I spent fiddle farting around in the driver's seat, the high side pressure got too high due to the lack of airflow across the condenser. The AC pressure sensor (on the high side) detected this abnormally high pressure and shut off the compressor clutch to prevent damage. By the time I looked under the hood, the compressor clutch was off and it looked like it had never engaged in the first place. Turns out it had engaged normally at first, and then was commanded off as a proper response to an abnormal situation.
The moral of this heartwarming story is to check the compressor clutch operation immediately after starting the engine. During subsequent troubleshooting, I did just that without realizing it. I started the engine by leaning through the open window to turn the key, and then noticed the clutch ran briefly. I then changed my troubleshooting approach and moved to post #4 for insufficient cooling. I had my A-Ha moment when working through that list and realized there was no airflow through the condenser due to the failed fan. Also, due to the toasty hot weather, I minimized my time outdoors and so did not run the engine for very long. Had I run the engine for more than a minute or two at a time, it would have overheated and provided another huge clue about the lack of cooling airflow. After I took care of the bad fan motor, AC operation returned to normal.
I encountered a little troubleshooting snafu recently with the AC, and wanted to share what I had found. During a recent heat wave (115F!), the radiator cooling fan failed on my car. Gory details here if interested:
Actually, that's not a conditional statement. Details are at the link even if you're NOT interested, but already I've digressed.
The primary symptom of the fan failure? No AC. My beloved wife (only got one, in case I have to be specific) had taken the car to the store, maybe only a half mile or so away. Two very short trips separated by at least 30 minutes, so the engine never had a chance to overheat even with the dead fan. Had she driven further, the fault would have reared its ugly head, but not in this case. However, she did mention the AC wasn't working at all. Initially I thought it was a combination of heat-soak and such short driving time, but sure enough, there was no cooling at all when I tested it in the driveway.
I followed my handy dandy troubleshooting guide and went to post #5 for no cooling. Time to confess, I actually skipped around a bit, briefly looking at several things and I tripped myself up. I sat in the driver's seat, started the engine, selected manual LO for cooling, and then looked under the hood. The AC compressor clutch was not engaged. That's a bingo! I had found the problem, or so I convinced myself. Turns out the compressor clutch did indeed engage normally when I first started the engine. But after the 20 seconds or so I spent fiddle farting around in the driver's seat, the high side pressure got too high due to the lack of airflow across the condenser. The AC pressure sensor (on the high side) detected this abnormally high pressure and shut off the compressor clutch to prevent damage. By the time I looked under the hood, the compressor clutch was off and it looked like it had never engaged in the first place. Turns out it had engaged normally at first, and then was commanded off as a proper response to an abnormal situation.
The moral of this heartwarming story is to check the compressor clutch operation immediately after starting the engine. During subsequent troubleshooting, I did just that without realizing it. I started the engine by leaning through the open window to turn the key, and then noticed the clutch ran briefly. I then changed my troubleshooting approach and moved to post #4 for insufficient cooling. I had my A-Ha moment when working through that list and realized there was no airflow through the condenser due to the failed fan. Also, due to the toasty hot weather, I minimized my time outdoors and so did not run the engine for very long. Had I run the engine for more than a minute or two at a time, it would have overheated and provided another huge clue about the lack of cooling airflow. After I took care of the bad fan motor, AC operation returned to normal.
Had my cooling fan motor seize up on my 00 S Type. First sign was AC (was driving) went bye bye... warm air then... the needle moved.
Luckily, I was able to get over and shut the car down before it overheated. (4.0 engine 😩 installed a replacement fan and all was well again.
A quick search on a new DCCV shows a massive difference in price , is it a case of you get what you pay for by buying a Jaguar part, or will the Bosch one or one of the other makes, be just as good? Thanks in advance
A quick search on a new DCCV shows a massive difference in price , is it a case of you get what you pay for by buying a Jaguar part, or will the Bosch one or one of the other makes, be just as good? Thanks in advance
Bosch made the OE one I believe.
You can get Motorcraft YG-355 (5-hose valve)
(For the later cars, Motorcraft YG-378 (2R8Z-18495-AA) (3-hose valve).)
From: Pawleys Island, SC USA (formerly from Tabernacle, NJ USA)
Originally Posted by markbam
A quick search on a new DCCV shows a massive difference in price , is it a case of you get what you pay for by buying a Jaguar part, or will the Bosch one or one of the other makes, be just as good? Thanks in advance
The first DCCV replacement I bought was directly from a Jaguar dealership. The valve body was stamped with the Bosch logo. It cost me way more than if I'd just bought the Bosch or Motorcraft brand in the first place.
The second DCCV I bought was the Motorcraft brand, as Jag V8 mentions. It was less than $100 at the time. While the box was labeled Motorcraft, out of the box, it too was stamped with the Bosch logo. And the only difference I could see between the Jag vs Motorcraft was the box. It seems I paid a lot of extra $$ for the Jag box! The part was the same.
So it looks like Bosch makes both the Jag and Motorcraft versions, which appear to be identical in every respect.
I would recommend staying away from any off-brands. This is not a part you want to fail because it was cheaply made. JJF
Last edited by Jumpin' Jag Flash; Sep 23, 2021 at 11:36 AM.
Reason: Additional text added
installed a replacement fan and all was well again.
