The AirCon of my XJR is acting weird lately. Often when restarting the engine after a short wait, the centre and side vents blow very warm and humid air, and it takes a while for the vent to blow cold air. Is there something wrong with the ventilation gates or the heater valve is not totally closed? Where to start looking?

 

There is a self test on the control panel that will get you started on the path

See page 110

The fault codes are in a TSB

http://www.jagrepair.com/images/TSB/...stem%20DTC.pdf

http://www.jagrepair.com/images/Trai...des/703_SG.pdf

 

Will see if the self-check produce any code. AirCon is often a difficult fix, particularly when most parts are no longer available.

 

There are ways around parts if it comes to that

The self test does not " show " everything

 

Aside from a self-test code, there's probably nothing to worry about, Q. You guessed it already. The heater valve is de-energised and hence OPEN when the ignition is off. So the matrix coolant warms up after shutdown. A design characteristic that really wasn't a good one, IMO. Another possibility would be a low a/c charge, which would take longer to overcome the heat and humidity collected by the matrix.