The Climate control unit is a common problem for the Jaguar S-Type built between 2003 - 2008
The fault is caused by a Short circuit within the Heater Control Valve which is fitted to the Coolant System.

PLEASE NOTE:
THE HEATER CONTROL VALVE MUST BE REPLACED BEFORE REFITTING YOUR REPAIRED CLIMATE CONTROL UNIT.

It will cause the heater to blow hot all of the time or complete failure of the heater/air-con system.
Your S-type will have one of the climate controllers pictured above depending on the year and version you have.
We can rebuild your faulty unit fitting an external circuit protector so