Jaguar Repair Problems? Ask a Jaguar Repairs Expert.
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The problem may be an air pocket, stuck thermostat, clogged heater core or stuck heater control valve. If the engine is warming to operating temp without a problem then the thermostat or air pocket is most likely not a problem. The heater contrl valve is the part that aloows hot coolant to enter the heater core. The valve is most likely mechanically stuck closed. You can disconnect the three wire connector on the valve or pull fuse #1 (10 amp) in the engine ocmpartment fuse box and the valve should electricaly default to full heat. If you still do not have heat you will most likely need to replace the valve. This valve is located on the passenger side bottom of the engine cooling fan above the sway bar bushing bracket.
I tried your suggestion with the fuse but no improvement. Want to take vale out but is it inside the car or outside by the firewall?