I have a 2008 XKR coupe with a problem with the air conditioning. The Auto feature does not seem to be working correctly. When the auto button is engaged and the switch is lit up, the fan drops down to its lowest speed. Manually you can adjust the speed thru its range with no issue, but as soon as you engage the auto feature the fan slows down again. This happens even when the car has been sitting outside in 100 degree + temperature. Has this happened to anyone else and if it did can you give me an idea of what is causing this problem?
Thanks for your help.

 

It should follow the temp demand, higher speed dependant on the temp difference between the cabin sensor and the selected temp. The heat side is dependant on the coolant temp but the cool side runs fast until the temp drops.

I suggest getting a good code reader that will read the chassis modules and see what codes come up with. Mine actually told me my A/C charge was low when it wouldn't cool the car reliably. I'm going with comm or module problem.

 

Sort of what Ranch just said, but I've experienced that MY fan on A/C doesn't go to High until the refrigerant temp gets into a cooling range. It usually takes a couple minutes on LOW, blowing warmish air, until the fan kicks into HIGH while on Auto.

 

Try cleaning the incar temp sensor first. They get covered in dust and can become blocked and then unresponsive to temps

 

Thanks to all for your help. It has already been at an independent shop and is now at the dealer for this issue, both have hinted that it might be the resistor in fan. The independent shop did not change the resistor because they could not find one so that is why it is a Jaguar dealer now. I don't know if this even makes sense because the fan will speed up manually. I'm at a wait and see point now to see what the end result will be from Jaguar Dealer. Thanks again for your suggestions.

 

It's not the "resister" which is actually some flavor of heavy transistor. You can find them on eBay for $8-12 for the Land Rover version which is a direct replacement. Drop the vanity cover, remove the wiring and then two screws and the module drops out of the air stream. Read the numbers off it and Google them for a replacement.