So I was about to plop down $150+ on a new DCCV for my '02 S-3.0 Jag.

The A/C works fine. The heat is non-existant. I did a lot of reading here and thought the DCCV valve must be bad. I was ready to order one. Then someone in another thread suggested I dig a little deeper. (At that point, I was not even certain where the DCCV lived.)

So I did some digging. Someone else here posted a pic and that helped me find the DCCV. Here is one I took.



The yellow arrow is pointing to the top of the DCCV. The Red arrow is pointing to the electrical socket and the purple arrow is pointing to the electrical connector. (The plug end is to the left in the photo.) The red clip on the connector has to be lifted (as seen in the picture) in order to remove the connector.

I checked the voltage at the connector and with the dash controls set at max (+85oF) there were zero volts at the connector wires. The left wire to center and the right wire to center both read the same. With the dash controls set to low (<65oF) the voltage at both sides reads 13.7v.

If I understand correctly from what I have read here, this indicates that the electrical system is functioning correctly. Am I correct???

Assuming I am correct with my interpretation, I did a little more digging. This picture shows the heater hoses coming to/from the DCCV.



I believe the top two hoses marked with yellow arrows are the driver and passenger side heater hoses. I think the larger bottom hose is the return hose. With the car just started for 2-3 minutes, the top two hoses got hot quickly and the bottom remained cooler. As the car ran for 5-10 minutes all three hoses became very hot and all three were too warm to touch for very long.

If I understand this correctly, this means that both valves in the DCCV are open and the 'coolant' is flowing through the DCCV and into the heater core. Am I correct about this????


Assuming I am, the problem must be with the door that closes in the heater box. How can I access it? Is it accessable without removing the dash? Is there a way to manually open the mixer door? How do I test the mechanical and electrical function of this part of the heater/AC system?

Summer is coming and I do not want to lose the AC since it is working very well now. So please show me some pics of the test points for this side of the climate control.... PLEASE!

Thanks for all the help. You guys are awesome!

 

Once the engine cooled down, I went back out and plugged in the DCCV electrical socket. Then I started the engine and let it run for a little while.

With the Dash controls set to low temp (<65oF), the two top hoses - pipes- remained cool.



That is the two marked with the yellow arrows. The lower hose was VERY hot. About the same temp as they all were when the electrical connector was disconnected.

So, I am pretty convenced that the DCCV is working correctly. Do you agree?

I crawled under the dash on the passenger side and I located the blower fan. I cannot seem to find the mixer flap/door control.

Any help on that? I searched for pics but only came up with three threads. This one and two others. Please give me some tips! Thanks.

 

I really need to know where the actruator rod and actuator are located for the climate control mixer box?

I cannot find it. Can anyone help me out with a verbal description or a photo or two?

Thank you much!

 

BugDoc, if you're certian the DCCV is recieving voltage and its valves are opening then you likely have an inside electrical issue. Inside the cabin are a few temperature sensors (one located in airbox located above drivers right leg, another infront of driver, another located below glove box). They sniff the temperature for the climate control module (located and attached to the rear of the dual climate control station. Either one or more of the temperature sensors are toast or dirty, or the module may have a burnt tracer lead (common problem for the "S"). Many members have replaced the sensors and recieved satisfaction, many removed then repaired the tracer on the module, others have simply replaced the module. One must be sure their DCCV is operational before repairing or replacing the module or the module will burn again. Use the forum search feature to discover then read the numerous threads discussing repairs of the climate control system. With no doubt several experts will jump on this thread to help you further. Goodluck.

 

I am pretty certain the DCCV and electrical signals are working correctly. See my diagnosis descriptions above. Is this not, how the DCCV should function?

I have done a good number of searches and read a lot of threads. There are only three on heater core door that come up in this search: https://www.jaguarforums.com/forum/s...earchid=856912

I am convenced that the problem lies in the climate mixer box where the heater core and AC heat exchange live. I am pretty certain the blender or mixer door is stuck closed. It could be the door is physically stuck closed or the door actuator is non-functional.

Can someone please tell me how to access these. I looked in the JTIS, but I cannot tell from their sketchs how to acess the heater box under the dash.

Help!?!?! Please!!?!?!?!? (Thank you in advance!)

 

I read in this forum that the burnt trace on the climate control module is not that likely on a pre 2003 s-type. That is just what I read I'm not sure.

There is a cold air bypas blend actuator it seems to be located behind the instrument panel

If you have a JTIS search Cold Air Bypass Blend Door Actuator it will tell you how to replace it. If you do not I'll copy what I have and paste it. I'll keep looking to see what info I can find

Googled it and found this http://www.fixya.com/cars/t6522327-b...ag_late_spring it may be helpful.

Good luck

 

01AType30: I think that link may be just the ticket. Several of the actuators for the blender doors seem to be accessible by removing the glovebox compartment. Hopefully that is not too difficult. I'll try to get pics along the way.

Thanks.

 

Good luck and keep us posted

 

From the link that 01SType30 posted, besides the location of the blender doors and actuators, this statement is most telling and encouraging.

"Check that the heater core is getting hot by feeling the two tubes. If they're hot, then the actuator is the problem. Very common problem. "

Since my two heater tubes are getting hot (only when the dash control is set to heat and not when set to cool), this seems to confirm my suspicion that the heat blender door (or its actuator) is not functioning correctly.

Does anyone now what the voltage readings should be at the electrical connectors to each of the actuators?

Thanks.

 

Maybe there are pinpoint tests in JTIS?

 

I found five blend door acuators looking at the JTIS

1. Cold air bypass blend door actuator
2. Instrument blend door actuator
3. Recirculation blend door actuator
4. Temperature blend door actuator
5. Footwell vent/duct actuator

All of them except #5 have you removing the instrument panel to replace.

 

If they're driven by the CCM/RCCM can it detect overcurrent and then report codes if it does? Much easier just to ask it if so.

Also, can it be instructed to operate eash in turn and you just listen whether each moves correctly?

Can any be seen with (say) a borescope so you could watch them move?

 

I'm still hopeful that this is the actuator that controls the heater/AC mixer door.

Re-Circulation Blend Door Actuator

1.Remove the glove compartment.
2.Remove the recirculation blend door actuator retaining bolts.
3.Disconnect the recirculation blend door actuator electrical connector.
4.Remove the recirculation blend door actuator and disconnect the control rod.
5.To install, reverse removal procedure.

But I'm guessing that the one that is faulty is the #4 (Temp Blend Door) in your list...

I'll let you know what I can see through the glovebox compartment when I have time to pull it out.

Thanks again. If you think of any other diagnostic tests to check any of the sensors, let me know. I probably cannot work on it until Saturday or Sunday.

 

The Climate Control Module (CCM) recieves info. from temp. sensors and if they or CCM are toast the blend/actuator doors will remain closed or shut. Most issues involving temperature and blend are either the sensors or CCM. In other words, you can fart around observing and testing the actuators only to be led to the realization that the sensors or CCM are at fault.

 

So do we have any electrical tests that can be done on the sensors to determine if they are functional or not?

I'm more than willing to try whatever it takes to resolve this. It is 15oF outside right now and I cannot drive the car (unless I get this worked out) because of freezing rain in the area for the next 3-4 days.

 

Some have cleaned the sensors and this cleared "it" up. If you have a "Smokers" car, it is often found that smoke has coated the sensors causing them not to read. Others just replaced them one at a time @ $20/each till it cleared up. Most found that the CCM had a burnt tracer wire because of a failed DCCV. I'm not sure if this applies to the 02 "S" but CCM is a known and common failure point for the "S". My CCM is burnt but stuck in heat cycle. I'll be repairing it this spring. There are several threads from a month or two ago going over diagnostics, access, and repair for the DCCV, sensors, and CCM.

 

It looks like the actuators are the same I believe its a stepper motor and potentiometer on all five according to the schematic you should be able to swap one actuator for another just to see if its the actuator. That would eliminate the actuator.

I'll keep checking on you, Good luck,

 

The sensors can be read via OBD but typical generic tools won't talk to the CCM. This is for the 2003+ cars like mine, I've not got an early car to try but I expect it's possible on them too.

 

I read some of the threads on cleaning them and I did clean the obvious in cabin sensor just above the ignition switch. It was pretty dirty... lots of fuzz. I'm not finding the other sensors, but I am obviously not as good at using the JTIS and some of you are. I'll keep looking unless someone can tell me where the other sensors are.

I think I read through most of the recent threads. I am pretty convenced that the DCCV is fine.

Does anyone know the "names" of the other sensors so I can find them more easily in the JTIS?

I'm assuming the CCM is an expensive part. When it "burns" does it normally leave the accuators stuck open or just in whatever position they were in when the burn happened? How can one tell if it is "burned".

Thanks again.

 

You tell me...

If I run the car with the temp to max and the fan speed to low and the the airflow set to recirculate....

the car after about 3-4 minutes will automatically kick the fan to high speed and open the flap to allow outside air into the cabin and kick on the A/C.

If I close the recirculation, turn off the A/C again and slow the fan... it will go through this cycle again in another 3-4 minutes.

Maybe it is sensing something other than temp. But it seems the CCM is trying to compensate for something it 'senses' is not correct in the cabin....

Is this a clue?