HOW DO I FIX THE PROBLEM

SOURCE: I have a 2004 S

I had the same problem and found that this is caused by the Dual heater Control Valve malfunctioning.

The DHCV can be purchased at Rock Auto Parts for around 150.00 and can be replaced in around 30 minutes. This valve controls the hot water flow for the heater core for each side of the passenger compartment and when it fails, it's default is "open" which allows the hot water to flow freeley for whatever side failed. It is located on the passenger side front about 6 inches down from the top of the radiator. You will need some patience and some mechanical skill to replace it but its not terrible.

SOURCE: 04 Jag S type middle air vents cool, sides hot. Recirc hot.

here is what you do. look on the passenger side front near the bottom of the radiator. there you will see the dccv or dual coolant control vavle. it will have your two heater hoses running to it and another hose from the radiator under it . once you have identified it , feel and look around it for any signs of leaking. barring any leaks, disconnect the connector, turn the ac/engine on and usining a tester , test for voltage on each of the three wires.if both outer wires have no current ( the middle wire yellow- will have current) then your problem is the control panel. if the control panel is not a navigation it is possible to easily repair it. replacing it can run from 600.00 to 1500.00 depending on who you goe to. oh by the way its still some data that you aint looked at. holla back if you need more help or a repair of the a/c control panel.

SOURCE: i have a 2003 jaguar s type , has cold air in

My car just had that same exact problem took it to the shop and they found that there was a short on the ac circuit board so they put a jumper on it and this solved the problem and checked to make sure the proper fuse was the proper size.

SOURCE: A/C only from center vent. Heat from side vents and floor vents.

sounds like the blend motor from hot to cold is stuck open half way allowing both temps to come into the car.