Hello all!
Been off here for a while, mainly due to crazy busy (finishing my PhD) and no probelms for the past year or so (until now). Anyway, too add to all the posts and threads about no heat/cold that I have been seeing, here is mine.
Just after Christmas, I noticed that I started to get to heat. Since I had already replaced the DCCV (twice) prior, I know that this can be a symptom. First thing I did (once it warmed up!) was disconnect it, knowing that without power it should be stuck open all the time (heat). Did that, still got cold. And when I was in there noticed that the DCCV was leaking antifreeze all over the place. So, there ya go I thought. Valve leaked, filled up solonoids and it was stuck closed. So, about three weeks ago I replaced the DCCV (fouth ones the charm right?). Bleed system, checked coolant, etc.. For the first few days I had heat, not as hot as it used to be, but I figured maybe still some air in there and it will clear out as its driven. Then I started to get no heat at idle. Started thinking the aux coolant pump might be on the way out. Then a few days later no heat at all. Thought the temp sensors may be bad (still original) so set it to max heat to bypass them and waited. Nothing. Then, turned the car off, went inside. Shortly after I had to go get something so I hopped back in the car and guess what, full heat, even at idle. I had left the settings to max from last time. Great! It fixed itself. Turned the temp down, got cool, like it should. But turned it back up to high and nothing again. So, it sort of seems like the DCCV worked at first, then leaked and filled up with coolant again. Even when the old one failed closed, every now and then I would get heat (figured the solonoids would sometimes leak and drain, then work for a bit until they filled up again). Anyway, that's the story. Now my wife is driving the car now everyday for the last few weeks and she still has not be able to get heat. So basically, here is my checklist of what to do, comments appreciated!

1) Check fuses
2) Make sure pipes from DCCV are hot with heat selected
3) If pipes are hot, maybe flush the heater core
4) Disconnect DCCV and see if I get heat. Maybe my replacement was bad.
5) If I do get heat, check the RCCM.
6) If RCCM is fine, atempt to check the wiring loom (don't want to do!)
7) I don't know!

Since when I did get heat it was hot at idle, I figure the Aux pump is fine. Also, all vents are the same temp, unlike when my CCM failed the first time so I think that is fine. Also, correct me if I'm wrong, but usually the board is fried when they fail open (heat), not closed (cold). I know lots of this is easy to check, but since its now my wifes car, I dont have access to it all day!

Thanks

 

I suppose if the valve is sticking (in any position) then you don't know whether the RCCM/CCM is working or not. Even if the valve is stuck the volts should change as you tell the system to heat/cool. You can test using a DVOM at the DCCV's terminals - centre is 12V, others are L & R which should have volts that head towards GND as the RCCM/CCM tries to close that side.

This site has quite a lot of help jaguarclimatecontrol.com/
so does Gus's site www.jagrepair.com

 

Thanks. I've been to that site before! It is really helpful. I guess if the fuses are fine and bleeding the system again doesn't do it, I'll have to think about checking the voltages. At least if I diconnect the valve again and get heat, it points towards the RCCM. Oh joy, I don't want to have to try and find one of those again! Maybe I'll just tear it apart and fix it myself if it comes to that! I'll try to check some of these things tonight (fuses, coolant levels, the easy stuff) and see what happens. Hopefully this weekend I can tear into it if I have to! I've done this so much now that it only takes me like two hours to replace the valve! (it was a 6 hour job the first time, so I'm getting better!).
Thanks

 

Update!
So, I was planning to give the car a good once over today, until my wife got home from work on Friday. She told me that she doesnt think anything is wrong because its working fine now and she must have just not understood what buttons to push (she still hasn't figured out how to use all the buttons and settings). Okay, so this morning took it for a drive, and there was heat! However, at idle there isn't. Basically under 1500rpm or so, its cool, above its hot. I drove with the car in 4th for a while on the highway (3000rpm or so) just to make sure if there was any residule air in there from refilling the system it would get forced out, and there was lots of heat. So, forget all my previous tests I was going to do (they all seem to point to the aux pump anyway). As far as I know, loss of heat at idle is due to the aux pump failing to work. Now, does this pump run all the time, or does it only work at idle/low rpm? The fuse and relay for it seem fine so other than grabbing a hold of the thing when the car is running and seeing if its working, what's the best way to see if it has failed, or if it is on the way out (there has been heat at idle one or two times since this all started making me thing its on the way out). Is there another relay I could swap out in the fuse box for something else that I know is working and see if maybe just the relay is bad? Suggestions?

 

Once the DCCV goes, ther CCM (climate control module) shortly goes thereafter. Send the CCM to the vendor on this forum for a rebuild ($120).

 

You're not telling me what I want to hear! lol I have this feeling that the RCCM is probably gone, or close to it. I have actually tracked one down for next to nothing (much less than the repair cost) so I will give that one a try once I get it and see what happens. I'll replace it with the one I found and then probably send the old one to get fixed. From my experiance it wouldn't hurt to have an extra one hanging around! Thanks for the suggestionsand hopefully a simple RCCM swap will fit it all. I don't think I've ever heard of a aux pump failing, so I guess that would likely not be my problem. So, this will be my third CCM and DCCV since I've owned the car (about 4 years). Not a good track record for these parts!

 

Does it stay cold when you are driving normally and the temp is set low?
If so it is probably not the RCCM.

 

Wouldn't a sticking thermostat do the same?

No heat at idle, but warms when vehicle is driven.

 

Rick makes a good point. Check that thermostat before you spend any more time or money on other possibilities....

 

Don't be too sure it's not the AUX pump! My 2005 STR had a leaking DCCV and I changed it. The heat/cool problems were reduced a lot. Then it got cold out and I started using the heater more. I had heat but not much and it never fully got roasting hot no matter how far I drove.

Swapped out the AUX pump (the old one does work on the bench with 12 VDC applied??) The new AUX pump got everything back to normal.

I still can't explain it but that's what it took to fix it. Someone suggested if I had bench tested it under load maybe it would have failed.
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To answer the question: When set to cold, no problem at any engine speed. I am still doubting the RCCM, but I got a chance to get one for $50, so I bought it anyway. Not a bad idea to have a spare one kicking around if you ask me! I hadn't thought of the thermostat, good suggestion. As far as I know it is the original one (almost 200,000km on the car now) so it could be time for a new one and as far as I know its not a pricey part and pretty straight forward to change. I am still iffy on the aux pump, but we'll see (I don't want to think how much fun that would be to change if the DCCV is any indication!). So, since the weather is not really a problem now and there is heat when driving I'll work my way through this without just replacing everything in a hurry. First, I'll check out the thermostat. Correct me if I'm wrong, but wouldn't I see some signs of overheating if it wasn't opening? Anyway, I may try swaping the new RCCM when I get it since it's easy enough to do. Finally, other than swapping the aux pump, what's the best way to determine if it's working? Grab a hold of it when the car is off and compare to when it's running!
Thanks

 

Could be a sticky thermostat, but once it's open it should stay open, do you get the same problem every time you slow down, even after a good run?

 

This happens every time the car is driven, whether short or long trip.
So, to sum up:

1) No problem getting cold air under any and all conditions (idle/driving)
2) No problem getting heat at above about 1500rpm or so
3) Just no heat at idle or when slowing down to 1500rpm or below.

From searching and reading clubairth1's post about his problems and replacing the aux pump, I believe that this is my issue to. It could still be a sticky thermostat, but since this problem is consistant and I can reproduce it at will, I doubt it is a thermostat since sticking should be intermitant and if it failed all together i don't think I would be getting heat and the engine would be overheating and the dash would be yelling things at me! I might try swaping the relay next to the one for the aux pump just in case it is a bad relay, but looks like I'm searching for a new aux pump. How bad is the job to change it out? I also guess I could check the connector again since I did just have it disconnected to swap the DCCV. Maybe I just forgot to plug it back in or it isn't firmly connected. I have been known to forget things like that.

 

Always do the easy stuff first.
Maybe someone will chip in who has done the aux pump before.

 

When I changed the AUX pump I first checked that it was running. I took the under car shrouds off and got my hand on the AUX pump. Had someone else cycle the key on and off. You can feel the pump turn on and off. Mine was running but I had the new AUX pump and was lost on what else to change so I just bit the bullet and did it.

If you changed the DCCV don't worry about the AUX pump. Yes it's a bit hard and be careful about breaking plastic stuff.

Your problem sounds similar but not exact to mine. Please post back if the AUX pump fixed it. Your symptoms match an AUX pump problem almost to the letter.

One last thing; There are two electric water pumps on the STR. The AUX pump and the IC pump. I think you know that but wanted to make sure we are talking about the same pump!
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Glad to hear it's at least no worse than changing the DCCV! I know what's happening seems to be the definition of an aux pump failure so we'll see. Hopefully it's just a bad connection and I forgot to do something in the hassle of changing that darn DCCV! If not, I'll do the key cycle and see if the pump is even turning on. And I do know about the IC pump, already had the pleasure of changing that last year! I won't get a chance to dig into this until next weekend but I'll make sure to keep you all updated on what happens! Even if it's a bad connection it will help others know what a non functioning aux pump will do!

 

Alright! Tore into the car today. And the findings are . . . dead aux pump! Got in there and checked all the connectors, they were good. Got my dad to cycle the ignition with my hand on the aux pump, no change. Didn't feel anything like it turning on. I even started the car and felt it, still nothing. Then, just incase I disconnected the pump and tried again just to see what it should feel like without power. Felt the same as with it connected. So, there ya go! New pump being bought and we'll see if this fixes it! I have checked the relay and fuses and they all look good, so looks like I've gotta prepare to dig in that engine bay and replace that thing!

 

 

good luck


nice one norri

 

I do the Heater valve and the Climate control modules together. The signal is a pulse width powered ground. The heater valve sticks and kills the module. I know it sucks but that's the way to do it. Sometimes you get lucky and only have to replace the heater valve.