Very little heat or air

Heater should have a seperate electric water pump. Fuse or pump itself may be bad.

check fuses

You probably have a vacuum leak somewhere going to your control unit.

heating blows only cold air on my jaguar xj6 on a p registration

five weeks ago my fan belt snapped and when i replenished the overfill to radiator i used only water

I have the similar problem with both my Jaguars, one is a 1988 Jaguar XJS, the other is a 1987 Jaguar XJ6, both blow COLD air out some vents while it blows warm air for heat. I heard it had something to do with the cold air blowing as a dehumidifier, I don't know if this is true, but it is really annoying to have both cold and warm air blowing when I need heat in these cold Canadian winters. If you find out please drop this website a note and let us know how you solved it. thanks.

could be related if condensation is on inside of windshield indicates heater core is leaking in heater box under dash on pass side car may be over heating check coolant level, coolant fan, and thermostat if working, also keep eye on temp gage if equiped

check the fan speed resister block... located under the dash in the duct work near the fan. i may have failed

Robert

A faulty temp sensor for the automatic climate control.

due to the fact there is duel zone heating in these cars there is a heater control unit could a amplifier these tend to fail and you wont be able to get any heat a genuine unit is very expensive around $1500 but if you shop around you can get one for around $250 non genuine
then its just a matter of getting a jag tech to fit it

good luck

vacumn pipes on the trampillias(vacumn diaphrams )not working right