Where is the temperature sensor for the AC located?

I found the temperature sensor. It is to the left of the steering wheel (probably only on LHD cars) mounted to the trim panel. It is plugged in but I have no idea how to test it. Still haven’t found the speed signal.
I am running out of time though. I know the engine temperature needs to be warm for the pump to run, and the car is only insured and taxed from March to October. So soon I won’t be able to drive it anymore.

I didn’t think that sensor had much impact on pump operation.
It’s more for the automatic climate control.
In any case if it was badly faulty there would be a fault code present. (you can read fault codes by holding down 3 buttons on the panel while turning the ignition on)

As advised above you would be better off checking the voltage with a lamp on the relay coil terminal pins. Check one side of the pin has +12v on it. (turn ignition on if you don’t get it)
Then check the other side coil pin gets an earth signal when the engine is running, climate on, set to Hi

All that is already checked. It is definitely the climate control not switching the control line for the pump to ground. The question is why it is not doing it.
I am tempted to hard tie it to ground and have the pump running whenever the ignition is on…

“I am tempted to hard tie it to ground and have the pump running whenever the ignition is on…”

My advice is to follow that hunch. Just make sure the +12 for the relay is from the ignition or accessory circuit.

It would be kinda wasteful if the pump ran when the car is switched off. :upside_down_face:

Yes, while the pump +12V is always on, the relay +12V comes from the ignition. So that should work without too much trouble.

Jaguar issued a Student Guide for all techs attending the training class Climate Control 703.
Here is my copy of the SG 703 that covers X300/X308/X100/X200/X400.

Have you gone into the self diagnosis mode?
Explained on page 110 of the .pdf (page 2.11.2 of the Student Guide) is how to place the Control Panel in that state to retrieve the DTCs.

Your Welcome.
x308 x300 703_SG.pdf (2.9 MB)

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Thank you, motorcarman, for the geekgasm!


Harold, check the manual out. That dang-blasted control module has a serious load of responsibilities. Just getting the pump running may not get you cabin heat.

Page 98 has the test procedure for the interior temperature sensor.

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Thanks a lot for the manual!
I need to do some more reading. When I bridge the relay for the pump I do get cabin heat. But reading the manual, I get the impression the heater valve should be closed when there is no engine speed signal. So I guess that means I must have an engine speed signal.
Maybe the heated rear window not working and the heater pump not working are unrelated faults.

Cheers,
Harald

“Maybe the heated rear window not working and the heater pump not working are unrelated faults.”

I’ve got US$5.00 that says the lack of engine speed signal is suppressing activation of the rear-window defogger. That kind of amperage REQUIRES power from the alternator.

I’d spend a hour chasing that signal back to the crankshaft before hot-wiring the pump solinoid.

I thought so too, but this

Makes me less sure about it.

I’ll chase it anyway…

I forgot all about this thread and posted in another one: X300 auxiliary heater pump - #19 by HarryE30

The engine speed signal is good, but the climate control module does not pull the water pump control line low. Connecting it to ground makes the pump run an heating works. However I have no temperature control an this is not a permanent solution. I am not sure what else to look at.