Can I get the cooling line diagram and a way to test the DCCV?

  • 2000 JAGUAR S-TYPE
  • 4.0L
  • V8
  • 2WD
  • 150,000 MILES
Blew a coolant line (the throttle body return line) on the way to work. I removed the plenum and replaced the line, everything back to normal except I have no heat. The car and cooling system are in great condition, the heat has always been good. The interior fans and climate controls are all working as normal, no heat under any conditions (driving/idle). I fully bled the system after repairs, no air pockets remaining. Car not overheating. Coolant lines get hot except the ones going to the heater core. Can you assist with a cooling line diagram and a way to test the dccv (heater valve) is there a fuse I can pull to shut off the heater valve, so it goes into bypass mode? I can't get my hand in there. Thank you
Tuesday, January 2nd, 2024 AT 6:40 PM

1 Reply

  • 108,772 POSTS

It sounds like there is air in the system or the dual coolant valve isn't operating. If hot coolant is making it to the valve and no further, the valve isn't working.

The valve regulates the flow of engine coolant to each half of the heater core. Two electric solenoids, which are individually actuated by the heater control module, are the control elements. Check to make sure nothing, as far as an electrical connection is loose or damaged. If all appears to be good, you will need to scan the can-bus to see if there are codes stored in the heater control module.

Here is a link that explains how that is done:

Let me know if you find anything and if you are able to scan the can-bus.

Take care,

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Tuesday, January 2nd, 2024 AT 7:54 PM

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