All along while troubleshooting my cooling issues got my 2006 S-Type 3.0L, I’ve thought Fuse 32 in the engine compartment box controls the AC Clutch and the DCCV. Hopefully, for my sanity, it really does.

But why does my Owner’s Handbook list Fuse 32 as supplying power to the AC Clutch and the “Auxiliary Coolant Pump.” I didn’t know I had a Aux Coolant Pump. Where is the mention of the DCCV?

Is the Owner’s Handbook wrong? Can anyone confirm?

Thanks.

 

Iirc it is the 1 in the same fuse. The valve shorts sometimes blowing the fuse and is telltale when the clutch doesnt come on the ac comp. More often the dccv blows the ground trigger circuit in the climate control module. These can be soldered to repair. I have a few i have fixed already and need to put on ebay....1day

 

You don't. It's only installed on the V8 models.

The DCCV is on the same F32 under the hood, even though it's not mentioned in the owner's handbook. See the wiring diagrams here:

http://www.jagrepair.com/images/Auto...cal-2006on.pdf

See figure 01.2 for fuse F32 in the front power distribution box. Note how it feeds three circuits, shown on other pages. Look for 70, 71, and 72 (drawn inside a box) on the respective pages.

70 and 72 lead you to figure 06.1. 70 feeds the DCCV, bottom left of the diagram. 72 feeds the aux coolant pump at the bottom right, but your car does not have this item.

71 leads you to figure 03.2 for the AC compressor clutch, upper right corner of the diagram.

 

Thanks for the explanation. My AC Clutch is working fine and I need to dig down and get the harness off the DCCV to check for 12V on the center pin and a Ground on the outer pins, as I continue troubleshooting my hot air at “idle and low speeds” issues.

 

for a quick and dirty diag. Clamp off the heater hose going into the dccv and see if that improves your ac. There is more involved to diag past that but that will tell you if youre headed in the right direction if after doing so the ac is cold.

 

I'll try to clamp one of the heater hoses before driving into the office on Thursday. Hopefully, I'll have cool air coming out of one of the center vents during the commute.

If that works, I'll try and get the harness off the DCCV for a closer look for corrosion around the pins or lack of voltage or a good ground.

The DCCV was last replaced in 2013, as well at the RACCM module behind the glove box. I hope those components aren't giving me problems again, as the control module was big money.

Thanks for the suggestion and stay tuned.

 

Hi Earnest
For a quick solution if you just want the air conditioner to work.

What to do.
Disconnect the heater from the firewall. There are three hoses. Looking at the three hoses from the front of the car. The hoses that you take off are the left and bottom ones of the three. You can use a brass connector (plastic garden hose connectors work but don't like the heat and will bend). Connect the two heater hoses, that you take off and join together with 5/8 brass barb fitting. You don't need to cut the original heater hoses.

To seal off the heater. Use a piece of the same diameter hose (about 3 inches long) you can seal the heater off until you do a proper repair. Put the 3 inch heater hose (approx) over the two open heater connections and connect together (it will form a “U” shape. You can then run full air only (no heater).

To save doing possible further damage to the circuit board from a seized DCCV. Disconnect the wiring plug from the DCCV and seal it off.

An example of the 5/8 brass fitting link Buy it where you want.



This fix will work if the problem is your DCCV valve being seized or, not functioning due to the circuit board. Not if you have another issue.


This is useful if you are in a hot climate where the heater is not used much.

Good luck
Paul

 

Hello Paul,

Sorry for the late response, but this is a great idea to get cool air. I'll use it as a last resort after checking out the DCCV connections more closely.

I'll also try to get the Scroll Compressor Piston/Spring modification done. It seems that is a common problem area for insufficient cooling at idle and low speeds. I just need some time to get under the car. And a refrigerant evacuation and charge to the proper.

Thanks for your help.

 

According to the workshop manual, do I really have to remove the front tire, splash shields and other stuff to gain access to the DCCV?

Looking from above, I can’t identify the main heater hose coming into the DCCV. I can clearly see the two hose for the heater core/vents, but where is the feeder hose? Can I locate and clamp this hose from the topside to stop hot coolant flow into the DCCV?

Thanks for your help.

 

Before getting lost in the weeds, do you even have a DCCV problem? I thought you had previously ruled that out, but then had one incident where the vent air went full hot and the compressor wasn't running. For that one incident, that was more likely to be a power supply problem, such as the loose fuse socket you have since corrected.

Remember, if you have a DCCV problem, you'd see vent temps higher than ambient. To be double sure, when the vent temp starts to warm up at idle (the original symptom), simply turn off the AC switch on the control panel. That makes sure the cold output from the AC system isn't partially hiding any unwanted heat from a misbehaving DCCV. If the vent temperature is not warmer than ambient with the AC switched off, the DCCV is properly closing.

For the moment, the only thing I'd suggest doing with the DCCV is making sure the connector is clean. See the pics near the end of the guide showing showing corroded contacts.

I'd also suggest sticking to one thread. Somehow you've got three threads going for the same issue, with plenty of good advice but it's scattered among different locations. This will make it tough in the future for the next guy to see the resolution.

 

Earnest while Pauls recommendation is certainly correct. it is the looong way around the block. just clamp the larger of the 3 hoses with 1 of those cheap plastic hose locking clamp pliers from Harbor Freight and coolant will not flow in or out of the core. if the valve killed the climate module it is too late doesn't matter if you unhook. The dash connector for the ground signals from the module to the dccv are on the left side of the dash behind the plastic cover on the end. Refer to the wiring diag. for the 2 pins and connector. The most common failure issues involving wiping out the ground circuits in the module is a coolant leak above the DCCV from the coolant reservoir into the solenoids and or an internal leak into the solenoids from the valve doing the same thing. Past that which I don't think is your issue since you said the valve is not that old is the rubber seals inside swelling and jamming open and not stopping the hot engine coolant. No matter how good a ac system is working it is NOT going to be able to overcome 210* engine coolant heat. Hell it just barely handles 100* Texas heat.
iirc that bulleting on the spring is nothing more than removing the valve once Freon is recovered, and swapping positions for the valve and spring so the valve is no longer functional. you don't really even need to replace the seal for the cover plate cause they don't leak.

 

3 threads? lol another factor on bad DCCV is if you have ac when you start the car and goes away as it warms up, yeah its not closing he DCCV

 

Well Brutal, it’s ironic you mention a leak. Yep, I had a leak and replaced the expansion tank a couple of months ago. You predicted the circumstances perfectly.

The leak was where the small rubber hose goes onto the nipple on top of the coolant expansion tank; was broken on the underside ( typical Jaguar sleuthing fashion) and was difficult to see from above. Just a small drip that was over several months. Kept wondering why I would occasionally smell coolant and had to add coolant occasionally.

But as you say, the sneaky coolant drip had a straight fall down on top of the DCCV. That probably explains why it’s all spotted up from spatters.

So after replaying all this in my mind now, the DCCV probably goes into a state of “kind of sorta” functionality to “not working at all. On some days, I have a little cooling at low speeds to none at all the next day. Then I had the now-memorabilia of full-blast heat in July about a week ago. But always cooling on the freeway, where I guess the ram-air effect through the condenser overrides a bad DCCV. Just a theory.

So what now? I would like to clamp the hot coolant feeder hose (inlet) into the DCCV and maybe unplug the wiring connector — taking it completely out of the picture and see if the AC performance improves.

But my heater hoses setup for my 2006 S-Type 3.0 seems to be different from what’s being described in the forum suggestions. For one, I can’t see where the hoses enter the firewall. I guess I need to remove some plastic panels. And most of the hoses are metal, not rubber. Maybe it changes to rubber just before entering the firewall. I can barely see anything in the area now. Auto manufacturers sure like to cover everything important with plastic panels nowadays. I miss my 1982 XJ-6.

My best clamping area would be around 12 inches of rubber hose between the DCCV and the side of the fender well, before the hoses change to metal and running n alongside the fender well.

Amazon has good three-dimensional photos of new DCCVs and I can clearly see four ports for hoses. Two for the heater core, one for the Return I guess, and a fourth port underneath the DCCV, which must be the main inlet port for hot coolant. It would be hard to see looking from above, as I have been doing.

Or I’ll use your suggestions and simply clamp the larger of the three hoses in an area that’s rubber.

Sorry for the long post, but I figure the more details, the better.

I’m looking forward to poking around under the hood this weekend for cooling results,! unless Tropical Storm Barry comes after me.

Thanks for everyone’s patience.

 

Clamp the larger of the 3 before the metal pipes. Dont worry or think about anything past this. The v6 is really easy to change the dccv. Unbolt, unplug and pull the thing up turning over uperside down. Remove the hoses paying attention to the way theyre hooked up. Not just the port but the top of each one as it is on the valve so theyre correctly positioned when you flip it over and reinstall. On the ac, the fact that you have some cooling tells me either the valves are only very partially open and or it is the pressure valve in the compressor. As i stated earlier, if the valves were open you would have no ac period, just hot air all the time except when the engine is cold. You can buy some cheap ac guages at harbor freight and see what the low side is doing and that is telling also

 

I did the ambient/vent temperature test tonight. The ambient outside temperature was 80 degrees and the driver center vent was right on with 80 degrees. So I guess the DCCV is operating properly, or at least for this test. Also, the ambient temp was recorded with my outside thermometer instead of the external temp sensor for the car, which displayed 69 degrees because of a storm front moving through the area earlier and I know this reading takes a while to show the actual temp.

And I'm still puzzled by the "hot air" and the shutdown of the compressor a few weeks ago. I plan to obtain a set of gauges in a week or so to take a look at the high-side and low-side pressures. Maybe that'll give more insight into what's going on with the system.

 

A little afraid to ask, but any updates?

 

Hello Karl,?thanks for checking in on me. Not much progress over the past few weeks and I haven’t been driving the car as much, especially on hot days.

I plan to purchase a set of gauges this weekend to check the low and high side pressures.

And if it’s low on refrigerant and will need to be evacuated and recharged to the proper level, I’ have decided to also do the compressor piston modification while the system is empty. Hopefully I can explain to the Indy shop what’s needed.

Stay tuned, as i’m really curious what the gauges will show and I might need a little help interpreting the results.

Thanks for everyone’s help.

 

Good call on the piston mod. Just do it. There's a PDF of the Jaguar bulletin in the troubleshooting guide, post #4. Print that out and show it to the shop. All you're doing is switching the spring to the other side of the piston.

As far as system pressures, I'm not very big on reading the gauges. The compressor's variable displacement feature makes it hard to interpret the gauge readings. It's somewhat of an exercise in futility. About all you can do is make sure the compressor can pull the low side down far enough, and that's about it. And if you try to interpret refrigerant level via the gauges, I shall hop the next flight to Georgia, track you down, and slap you.

 

Have been. Waiting with bated breath. Did you change the channel and not tell us? Been wondering what would be found with the world's most analyzed HVAC system.

 

Very good info! Thanks