cooling fans won't run
 

Hello, the forum -
On my 2000 XK8 (n/a) I have a problem with the cooling fans. I've had the unit out of the car and tested it using 12 volts, and the fans run fine. I've also tested the temperature sensor by removing the crossover pipe and using an ohmmeter and various water temperatures - it works as expected. The fans will not turn on at operating temperature, and they also will not run when the AC is engaged. Anyone have suggestions about what to test next? I've read that some models have a fan relay somewhere in the vicinity of the radiator housing, but I have not been able to uncover one on mine.
Thanks for any attention you can give this request.

And now, an update. Jaguar certainly took a few years to figure this one out: I've read descriptions fan control module locations all over the front end of the car, but I finally located mine, inside the driver side front fender underneath the headlight housing, behind the horn, accessible flat on your back. I'll be ordering a new one if I can find a vendor.

Try AutoReserve in the UK for the relay. They supplied me one a couple of years ago. It was obviously used but they test before selling. It will save you a lot even with postage. I'm in Australia.

x

Check also fuses #12 & #14 (both 30A) in the engine compartment fusebox.

The part # for the fan control module is LJA6702AA.

Thanks, Redjags. I found one described as "serviceable used" on eBay, now awaiting its arrival. Given the rarity of these parts, which apparently are out of production without a third-party having stepped in, it would be good to know if and how they are amenable to being rebuilt

Thanks, michaelh. I have checked all the fuses, they appear to be in good shape

There's nothing complicated about the control module on the 4.0 cars - so they can either be rebuilt or a brand new one built from scratch using standard automotive relays. The module either connects the fans in series or parallel, depending on how fast the computer wants them to run. IIRC Pistnbroke rewired his so that one fan is always on - making the wiring for the second fan even simpler.

Are you sure the engine is getting hot enough? They don’t come on till 95C…. At least on the XJ8, can’t see why it would be different on the XK!
https://cimg8.ibsrv.net/gimg/www.jag...8c36088e1.jpeg
From the XJ8 workshop manual

On 4.0 cars They should come on with the A/C regardless of engine temperature (unless today is one of my crazy days), and I think the OP mentioned that they didn’t.

The manual seems to indicate that it will only turn on when the AC pressure gets to 12l bar 174 psi.
If his gas was low to start with then it wouldn’t instantly turn on. I had it with my own car that the AC had to be on for a minute or two before fans kicked in.

I don’t know the A/C system pressure with a fully charged system.

on my 2002 XKR the fans come on as soon as the A/C is toggled on.

Z

Fans on my 2000 XKR do not always run with A/C on. Definitely system pressure sensitive.
Had a very hard time a couple of years ago testing fan status.
By far the easiest way to test is resistor in engine temp sensor plug.