Jaguar Repair Problems? Ask a Jaguar Repairs Expert.
First need to check the air conditioning pressures are to make sure they are ok. If so then we most likely have a problem with the heater valve. We can perform a test with a digital multimeter. Go to the left side dash and remove the side panel. You will see some connectors. We are looking for the green connector. Use a light and you will see each wire pin numbered. You are looking for the 14 way green connector. Make sure the key is off and disconnect it. With a voltmeter check for power on pins 9 (brown/green) and pin 10 (brown/white) on the harness side you disconnected. If power is present then leave the black lead of your meter to ground, reconnect that harness connector to the dash then start the engine and turn the climate control to full a/c. You should read low voltage on both pins and you should see it change as you increase/decrease the temp on both pins. If the voltage stays high you have a bad module and the valve is mist likely shorted.