So, I have an 89 xjs. The cabin climate system really doesn’t seem to be connected. I only blows ambient air. Neither cold in the summer nor hot in the fall. Have had the ac rebuilt. Had new blowers put in. I have a man/auto system and operate on manual. Just not sure where to start my trouble shooting. Any suggestions would be appreciated. Thx Jeff

 

This manual might help. Your car has the MkIII Delanair system.
Both electronic servos and pneumatic actuators are involved in the operation of the system, and both need to be in perfect operating order. I'd start withe the pneumatic system, and verify whether you have vacuum when you should at the various actuators. For example, when the system is set to full cold, you ought to have vacuum n the heater valve to close it. The heater valve is in the middle of the firewall at the top of the engine bay, right in back of the engine. Verifying vacuum at each actuator, to include the two blower housings, and the defrost and center vent actuators at the appropriate times should be verified. Vacuum comes from a port at the rear of the right bank of the engine. It is stored in a vacuum tank and controlled by various solenoids operated by the Delanair computer.

You can also verify if the servos that operate the flaps controllong passage of air thru the heater core and evaporator operate by moving the temperature controls from cold to hot.

Is the compressor clutch operating when the system is turned to full cold?

Start testing and let us know what you find.
https://www.jaguarforums.com/forum/a...troduction.pdf