Hi,
I recently ran the climate system diagnostic, The attached files should have everything to test the functions.

 

Thank for adding those here, that is way above my tech skills to figure that out. But it is a useful post.
darryl

 

Nobeel,
WOW! Crazy good info.
Thanks!

 

I was wrong, my 1996 VDP has ~250k miles
Heater only blows ‘warm-ish’ air at HIGH, not blistering hot like it used to.

SO FAR:
I pulled the heater auxiliary pump and it was a dead short.
Bought a heater pump for a Sprinter van ($50 as opposed to $581 for the Jag-brand) and installed it. (Thanks, Barchetta for the tip!)
Since I had to solder on the Jag harness connector, I double-checked impeller rotation to make sure it ran the right way.
Checked voltage at the connector and it’s 14V with engine on.

BUT, the hose going to the heater matrix is not as hot as the supply hose to the valve as it comes down the sidewall.

AND, the voltage to the Valve is 14V when the heater temp control in the cabin is all the way DOWN, and only 6.8volts when the heater temp control is at 90 (all the way UP).
The SAME temp of air blows with the heater temp control set at 90 or way down low (but not so far down as A/C range).
Heat does NOT increase when the valve connector is disconnected (that is, when it should be fully open).

MY DIAGNOSIS:
The valve is the problem.
I assume (and have read) that the valve is a normally-open voltage-driven proportional valve and it is stuck in a partially-open position.

MY QUESTION:
Should I replace the valve or try a repair?
I ask, because 250k miles is a lot of cycling on that valve.
Note: I'd buy a used valve off of Ebay or some such, the new Jag vlave is $400 or so - yikes!

 

Did you try give the valve a good smack?
it would not be the first time a component on a British car was brought back to life by a percussive persuasion.

 

Barch,
Yes, the Technician's Tap was applied with various degrees of vigor.
Though I like 'percussive persuasion' as a bit better of a descriptor.
:-)

 

OK, OK, so I shoulda fixed this ages ago. I get one demerit.
Now that's settled:

I ran the self-diagnostic.
It beeped and checked each value four times (took a total of maybe 6 minutes to cycle through them all!)

Is that normal?

When I first turned on the diagnostic stuff, it 'reported' (showed on the LCD) 24 then 45 - are THOSE error codes?

After it had cycled through all the tests, it still blew cold (well, I didn't do no fixin' yet, eh?)

And, when I opened the bonnet and checked hose temps with my hand I found the the long hose that goes from the water pump all the way round and back into the rear end of the head was hot.
BUT - the output hose (that is the one I'm pointing at in the pic) from the valve was COLD AS ICE!

My expert opinion is: "The Valve she be Broken!"
Am I correct?
And, yes, I whacked the valve a few times to get its attention, but no change was observed.

And where's the best (i.e. cheapest) place to get another valve?

Thanks y'all!

 

G’day Chuck,

If it’s the same valve as on my car then it opens when powered off so unplug it and see what happens.

If it has failed shut then it must be jammed or filled with scale.

The valves are pretty simple and easy to take apart and clean out so I’d try that first.

Cheers,
Jeff.

 

Jeff,
Thanks for the thoughts!
I seem to remember pulling the connector to test it that way, but had no thought of cleaning it.
I'll tear it down and see what I find.

Thanks!

 

They are error codes (see attached) and refer to face vent switch and servo, so not talking about the heater valve, but as the manual says, not all errors which can be seen by Jaguar PDU have a LCD code….

 

 

Here are a couple of pix you might find handy.

Cheers,
Jeff.

 

Thanks, Cafcpete, for the error codes!

The error codes say:
24 - Face vent differential temperature control
Yep! Never has worked as advertized

45 - Center vent servo
Not quite sure since I'm not sure what this does.