Is the AC evaporator, which appears to be right in front of the heater core, located behind the glove box inside the cabin?
Just trying to map out where to find a thermistor that plugs into it on my journey to get ac working again.
thbanks, John

 

The main heater/AC unit straddles the center of the console and is reached by removing the lower fascia panels. It is basically directly behind the AC Control panel and radio. Drop me a PM and I will give you access to my drop box where you can download a PDF copy of the tech manual.

 

Thanks sent.

 

Bearing in mind the scale of the job in getting to that sensor, or even its connector for test purposes, I would be inclined to re-think the way ahead.

Note that all the self test faults (and some others) are also identified by fault codes in the form B****. These would be able to be read by the elusive PDU, but might also be picked up on any Jaguar enhanced diagnostic scanner if you can access one.

None of the faults identified by the self checking process should, in themselves, cause a major climate panel button failure that prevents the test itself being conducted, so the chances of that heater core thermistor being the culprit are not great I would suggest?

Having checked all three power supplies to the module plus the AC Isolate Relay (in the right hand fascia fuse box) and the connections to the switch panel and the module, my suspicions would be the switch panel itself or the climate module rather than any of the sensors, but other than by B**** codes or trying substitute items, I don't know how they can be tested. Maybe other members might help there?

If you want to, it should be possible to carry out some remote testing of the sensors where they all connect in to the climate module. Many of them share a ground wire to the module, so it would be necessary to disconnect all the CC module plugs to prevent any unwanted cross connections while checking them. Probably wise to disconnect the battery before making any disconnections. That reminds me to ask if you have checked that the battery is in good health and whether a temporary disconnect of the battery has any beneficial effects on your problem

 

Astromorg, great ideas thanks. Heres where I am, and I invite comments / coaching from all.

PDU - can't seem to findton independent with this. Jaguar service centers around here NJ , USA all give same price quote: $169 to run a diagnostic.
Moneys tight so trying to make best choices.
Every XK8 tech documents say same thing. Only 3 conditions will display ER and store no codes faulty:
inside ambient temperature
Solar sensor
Heater matrix thermistor

I got to the 1st two. Each show several volts, a good thing.
Yesterday I went exploring. Found that 4 Phillip's screws on top, 3 torx screws underneath, and the entire glove box assembly comes right out. (Note to those who do this: there are 2 thin female connectors on left side providing 12volts to internal glovebox light)
With this out I could see and kind of get to the AC controller. This is the unit that processes 122 input wires across 4 different connectors.
Astromorg, with the document you posted I have the pinout of each connector. It's going to be a bitch to get to, but I can identify and measure the volt input of all 3 critical sensors mentioned above.
I posted the question that started this string today hoping that I might have easier access to the heater Matrix sensor itself than I will go through getting a reading from the controller connector.
I'll know more when I get to Vern's document, but it looks like reading the voltage at the input connector is tomorrow's work. Frankly this would identify an open wire, which I'd never see with a measurement at the sensor anyway.
FYI: the heater Matrix thermistor costs $125.
Jaguar diagnostics $164
AC controller: new $1200, used $30 - $40
climate control display used: $30 - $40

John

 

Bad news. I pulled the glove compartment and read the voltage input from the key sensors- they all test good to the ac controller.
looks like tomorrow I'm dissecting the center console to get to the climate control. If no good I'll be making my 1st trip to a Jaguar service center - ouch ;-).

John

 

If you decide to take it in for service, find an experienced automotive A/C shop. You will be much better off there than at a Jaguar dealership....

 

Thanks Jon, I planned on the dealership only because all the manuals end the fault diagnosis with: if that doesn't work hook up a PDU (dealer diagnostic sw). Not sure I'll ever find someone around here with that s/w - I just want to ID the defective component.

But thanks for the comment.

John