If you want to know the true coolant temperature use an OBDII tool that can display your engine temperature.

 

I have IDS. I didn't have it hooked up today. I also have a Matco Detetminator but doesn't do well on Jaguars as far as reading HVAC inputs..

I typically can get it fully bled on the second run but not having the aux pump operational complicated matters.

 

I didn't have the scanner hooked up today but knowing the car when the fan speed ramps up it typically means the temp is climbing.

The needle was a touch to the right of center so temps were more than likely in the 220 - 230+ range. Once the aux pump was running the needle moved back to center and the fan speed diminished.

Before when I had IDS hooked up I could see the duty cycle of the rad fan decrease (meaning increase in output) as the temp rose above 215 degrees.

 

Sounds like you really need to get that aux pump sorted out. I was thinking it was only for better heat at idle, but I'm having second thoughts. I have a training manual that mentions the aux pump operation. I vaguely remember it mentioned it helps improve overall coolant flow (at idle), not just heater output, but don't quote me on that. I won't be able to check until tomorrow night. Sorry about the wait. Anybody else know? Don't be afraid to jump in.

Since the ACCM controls the aux pump, how difficult is it to swap in your spare module?

 

Agreed on the Aux pump. Not difficult to swap out the ACCM. The only problem is early on when I swapped out the ACCM I still had no aux pump operation.

I'm truly starting to lean towards a wiring issue in the harness loom but going to swap the ACCM anyway and reconnect the DCCV plug now that I have an operating DCCV and keep my fingers crossed.

We know when I swapped out the ACCM before the DCCV solenoids were stuck closed (not sure how it would show in IDS)...

 

As promised, here are more details about the aux coolant pump, taken from a Jaguar Climate Control Training Manual:






A few thoughts, in no particular order:

Try these items one at a time. Don't do multiple steps at the same time, so you can keep track if anything helps or not.

Before swapping the ACCM, reconnect the plug on the DCCV. See if you can at least get heat when the aux coolant pump relay is jumpered. This will help determine if the ACCM is commanding the DCCV open.

Have you tried swapping in a known good relay for the aux coolant pump? I think you said you tried that, but can't remember.

When you have the ACCM out, run a jumper to ground from pin FC27-18 on the connector. This will mimic the ground signal from the ACCM to energize relay #5 and power the aux coolant pump. This will test the pump, the relay, and the connecting harness. This will help eliminate the need to wring out the wiring harness.

As far as bleeding the system, how much and what type of driving have you done? On my V6, it took about 50 miles, including some freeway driving, to settle everything down. If you're just putzing around town, that may not be enough.

Don't get discouraged, as you have been making good progress. You've found and corrected two faults so far, the failed thermostat and stuck DCCV. Now it seems you've got a third problem at play, so this whole scenario is well outside the norm.

 

Thanks Karl.

This is helpful for sure.

This is now literally the 5th or 6th time I've had to bled this cooling system. I can report back it is indeed fully bled. Coolant level is steady in the expansion tank and I now have heat out the vents and floor ducts and I drove her only a short distance tonight.

I'm going to perform your suggestions, step by step on Sat and see what happens. Just as a side thought I wonder if the ACCM doesn't get a reading from the DCCV since it's currently disconnected (or better yet senses closed solenoids due to them being stuck) would not send the ground signal for the aux pump.

I mention this as when I monitored the aux pump on/off operation and each solenoid duty cycle via IDS early on before removing the DCCV each solenoid duty cycle was reporting back fully closed despite ACCM commanding full heat (we now know why) and the aux pump "off" signal was refreshing on the screen (as though the signal was going out to command on) or maybe I'm thinking this theory too much...lol

I did swap relays early in a known good one.

Thanks again for the info, it's extremely helpful.

 

i suspect the DCCV solenoid feedback is not very sophisticated. It can obviously tell you what has been commanded (duty cycle) but I doubt it can report back whether or not the two valves have actually responded.

 

+1
It puts out a (PWM) signal but has no sensor to tell if the valve obeys the signal.

I suppose it might try monitoring cabin temps or some such but the delay would be huge so tough for it to tell if the signal was being obeyed.

 

Hi Guys and Merry Christmas!

I tried the above today and here are my findings:

The general good news is I have good heat regardless of aux cooling pump operation!

I plugged in the DCCV connector before starting car for the day. Started car, set climate control to "auto" - 85 degrees. Climate control fan did not put out anything showing delay was working as expected.

I let the car warm up at idle.

Within 5 minutes of starting car both heater tubes were hot to the touch. Temp out of center vents @ 113.2 deg F. (temp needle was a tad shy of middle position as she was just about to get to center on gauge)

Outside temp was 64 degrees. Car was in the sun.

I then lowered the auto setting to 65 degrees, AC on. After a few minutes temperature out of the center vents was now coming out at 50.9 deg F.Heater tubes were clearly cooler so DCCV solenoids responding accordingly to user inputs from ACCM.

Then I raised the setting back to 85 degrees on display. Temp raised back up to 107 deg F out of center vents. I then removed the R5 relay and installed the aux pump jumper. Output temp increased to 118 deg F.

I removed the jumper and the temp output decreased back to the 106 - 108 degree range, temp remained steady after a bit of driving. Don't get me wrong the cabin was very toasty regardless of the aux pump.

Then I raised the setting to "hi". Output temp increased to 132 deg F. out of center vents even though hi setting defaults to floor vents. When I jumpered the aux pump the temp increased up to 157 deg F. out of center vents.

I removed the jumper, output temp started falling and reinstalled the relay and wedged my pen between R3 and R5 and output temp started climbing again remained in the 150 - 155 deg range. Wondering if one of the receiving tabs in the relay connectors is not making a good connection to relay. (My "jumper" is 12G wiring - clearly thicker than the blade on the relay)

I then hooked up IDS to monitor output signals from the ACCM.

I think IDS may not be able to properly monitor the ACCM outputs. Here's why I say this. The ACCM output command signal for the aux pump from ACCM says "off". (Even said "off" when I had the aux pump jumpered on)

There may indeed be a signal issue from the ACCM. (I do plan on grounding out the aux pump pin to ground to see if I get aux pump operation before swapping out the ACCM)

However, the ACCM output signals for both DCCV solenoids also said "zero" while changing temperature setting on the ACCM but clearly the DCCV solenoids responded as the output temp at vents lowered, meaning the solenoids closed up restricting flow of coolant to the cabin and then opened allowing coolant flow after I raised temp setting.

Also, coolant temperature remained steady between 200 - 202 deg F. throughout all above testing as I monitored this output as well.

So... DCCV working with plug connected, aux pump could also be working and I have good heat regardless of aux cooling pump operation.

I will swap out the ACCM for the other one I have to see if that makes a difference with the aux cooling pump but I'm pleased the DCCV solenoids are responding to temp inputs as in a few months AC will be a necessity...

Again, as a last resort I will find a 12V ignition on source and wire the aux pump to a switch in the cabin for manual on/off operation.

Thanks.

 

Sounds like you are on to something here. If nothing else, you deserve an award for perseverance. You've already confirmed and replaced a bad DCCV and thermostat. Looks you're in the exceedingly rare triple fault category.

I'm not sure how best to repair a loose relay socket. Is there any decent access to the back side? If not, what if you left the socket as is, and twisted the relay tab slightly to compensate? Not perfect, but perhaps adequate.

As far as the fluctuating duct temps you are getting now, I wonder what range is considered normal. Once you fix the loose relay socket, you may not really have a problem. In auto mode, the controller is going to adjust fan speed and temp to maintain a desired cabin temp. The system may not really care if it's using 120 or 150 degree air.

 

Hi Karl,

I'm thinking about wedging the relay receiving female tabs out a tad with a small screwdriver to ensure a tighter connection to the R5 relay spades.

It can easily be accomplished from above.

I did remove the entire front fuse box assembly to check the aux cooling pump harness previously and will never do so again...lol with all that brittle Jaguar plastic.

The good news is all the temps attained today, whether the aux pump was jumpered or not were A OK in my opinion. My inputs made the output temps fluctuate and I think we stumbled onto a way to field test aux pump operation via monitoring discharge temp at vents if anything else... I'm glad my auto settings are working as designed.

I can tell you the AC discharge temp was spot on based on ambient outside temperature.

And from what I read the output temp of 113 - 118 degrees with auto setting at 85 degrees was also spot on andheat vent output north of 140 degrees with ACCM set to "hi" is damn hot, toasty and lovely...

Also, general coolant temp steady at 200 degrees, coolant level perfect in expansion tank, steady coolant level without any loss and no leaks and now working heat!

I also forgot to mention I checked the IR temps at the metal heating pipes in the engine compartment they were both equal to general coolant temp with ACCM set to "hi". Return pipe a tad cooler as normal.

I will dig a bit on the ACCM for kicks and report back as hopefully this will be additional good guidance for others.

Thanks for all your help!

 

Why not put a stethoscope on the heater pump to see if it is running.

 

Don't laugh Gus but I don't have one at this point... lol and it's hard grabbing the aux pump as there's no space in that engine compartment.

 

Going well so far - persistence indeed.

Before connecting the other module maybe meter out the wiring for the aux pump in case it's shorting or some such - to avoid damage to the other module. (It may have internal protection but I wouldn't assume so.)

 

I will do that JagV8 but here's a theory I'm toying with. The ACCM I had to replace a few years back was sourced "used". Not sure if it came out of a V6 or V8 car - back then I just needed it in charcoal. (Now I know better as the internals can be swapped out)

Now, my biggest issue is the ACCM command for aux pump "on" is absent from IDS signal monitoring. It shows "off" despite all the factors being present to signal the aux pump "on".

I noticed the descriptor on the screen says "ACCM command signal for aux pump".

If the wiring was indeed open somewhere between the ACCM harness and F5 relay the command signal would still be present from the ACCM, correct?

In looking up the ACCM part there's no mention of differing units for V6 (no aux pump) and V8 models, just different colors.

Wondering if the ACCM is programmed out of the factory to put out a aux pump signal regardless of being installed in a V6 or V8.

That lack of aux cooling signal output from the ACCM as viewed in IDS is troublesome but then again no signal outputs for DCCV solenoids either but they are working...

I would rather not go chasing wiring at this point if I don;t have to as if there is a wiring issue it would be in the harness between the ACCM and front distribution fuse box as all else checked out good...

 

I don't know if they (V6/V8 modules) differ or not as regards the aux pump output, sorry. (Never needed to know.)

It sounds like it would be simpler for jag to make them all the same and even drive the aux signal regardless, then just not have it connected in the harness (or fuse box or ...).

 

Do I understand correctly, once the relay socket is fixed, that you will have reliably toasty heat again? After that, the only issue is your scanner with non-Jaguar software is having trouble displaying the status of a system that seems to be working well? If that's the case, it's probably time to unplug the scanner and step away...

 

I'm not 100% sold on the loose relay terminal theory just yet. I'm going to do more pin point tests to rule out shorts, voltage issues, and ground out the aux pump terminal on the ACCM with a fused jumper to test for operation.

I found a good, step by step pinpoint testing document on the LS Forums for troubleshooting aux coolant pump issues

For all I know the aux pump might just be working after all as the cabin is nice and toasty at idle, auto settings and baking the cabin on "hi" setting.

It was 30 degrees tonight and it was a balmy 84 degrees in the cabin within 10 minutes of starting the car.

PS - I took apart my old DCCV tonight. Each cap was full of coolant and I totally took the DCCV apart. Both solenoids were stuck shut. Lots of cheap rubber on these solenoids that shrink and disintegrates... In my opinion.

I know your following the other lack of heat thread on the forum.

The OP installed a DCCV he purchased from a junk yard for $24...

 

Guys, I think we can chalk this one up as RESOLVED!

I took the Jag out for a drive around town to run a few errands. (which by the way I have taken back from my son - he now drives the Honda Accord...) Set ACCM to "auto - 85 degrees"

Nice heat. I also monitored heat temp output from floor vents throughout.

Good heat when driving, good heat at idle. I do think the aux pump is finally sorted w/o having to meddle with the ACCM.

When stopped at a light, engine at idle I saw a slight temperature increase from the floor vent indicating the aux cooling pump is now doing it's job. There was lots of information on the aux cooling pump operation on the LS forums.

So, I'm going to hold off on touching anything else at this point as all seems in order with the aux cooling pump!

Sorry for the long posts but hopefully this information will be of use in the future.

To Recap

Original Issue - No heat under any driving conditions, even with ACCM set to "hi" and DCCV plug disconnected (default heat) DCCV pipes cold despite hoses going to DCCV hot.

Actions Taken:

* IR readings of all hoses and monitoring of coolant temperature, including temps of each metal line going to heater core from DCCV. Based on lower than normal readings after engine was fully warmed up and experiencing a prolonged warm up period I discovered a partially failed thermostat. Testing confirmed old thermostat was opening 25 degrees too soon. Replaced with OEM unit.

* Originally used a Matco Determinator to monitor HVAC outputs, lead me down a dead end showing wacky evap sensor readings, which were false. Hooking up IDS showed true evap sensor readings, which were actually spot on.

* DCCV (Metrix unit - new but less than 6 months old) both solenoids stuck in closed position. Confirmed after taking DCCV apart for inspection.
* Additionally, suspected aux cooling pump not operating as designed. (After removal of the aux cooling pump it was dripping coolant from one of the screws on the bottom of the unit) Replaced.
* Replaced DCCV with new Motorcraft YG-355 unit.

* Performed the following to troubleshoot aux cooling pump operation - no 12V signal to aux pump with engine warmed, at idle, ACCM on "hi":
a) Checked harness from plug to front distribution fuse box, including the vehicle harness that runs under front bumper and under distribution box to rule out a short or broken wire/ground. Also checked all ground points.
b) Green plug on driver's side of dash.
c) Swapped R5 for another relay. Checked fuse 1 in front distribution box - checked good.
d) Bench tested both relays for proper operation w/ 12V applied.
e) Jumpered terminals 3 & 5 on R5 relay to confirm pump operation, including when bleeding cooling system after DCCV swap.
f) Double checked female terminals in front distribution box for R5 relay to ensure good contact to relay.
g) Checked all evap/temp sensors to ensure they were still operating within parameters. (With VCM/IDS monitoring)
h) Monitored coolant temp and outlet temps at floor/vent outlets during driving conditions in "auto" and "hi" modes.

Below is a link for climate control troubleshooting. It's for a 06 Lincoln LS but many pinpoint tests are spot on.

2006 Lincoln LS Workshop Manual

Also, to self check the ACCM for the 2000 - 2002 S Types press "off" and "floor" buttons simultaneously, than the "auto" button - the ACCM will give you codes (minus the C) then press any button to delete the codes and the ACCM will reboot.

A special thanks to everyone for their help. Glad to have a toasty S Type again!

PS - I would highly advise to "cycle" your solenoids once weekly. Bring temp from 85 - 65, leave for 2 - 3 minutes then raise back up to 85 (or desired auto temp) this should keep the solenoids from sticking in a position.

Thanks