- Lost heat.
- The location for the auxiliary heater core pump and heater core control valve is under the antifreeze coolant reservoir on the driver's side.
- Checked voltage to the control valve. Proper voltage.
- Checked auxiliary pump. Good to go there.
- Removed control valve and checked to see if heater core was blocked. Nope
- Did a direct connect to the heater core. Oh yeah baby, copious amounts of heat.
- My 16 year old control valve stuck in the closed position not allowing antifreeze to enter the heater core.
- Ordered new part from FleaBay.
$98.00 that included shipping.
Part from my authorized local Jaguar Dealer, $525.00. yeah pass on the Dealer this go around.
- Did a heater core bypass. Didn't want to put to much pressure on the heater core while I was waiting for the part to arrive.
- New used unit installed. Ready for winter.
- And the pics tell the story.

Not to hateful of a job to do yourself.

 

The control valve is not a constant on or off but pulses to regulate the heat to a target value

This regulation is dependent on 2 clean cabin and outside air temp sensors

There is a control panel self test to give you codes , but doesn't show everything

See page 110

http://www.jagrepair.com/images/Training%20Guides/703_SG.pdf

The dedicated water pump electric brushes wear out and can be replaced easily

Herd you can hit the pump with a broom handle and jostle the brushes enough to get more life

Somewhere around 2003 they switched to a less expensive Bosch unit for the coolant pump