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Richard, Jaguar Technician
Category: Jaguar
Satisfied Customers: 15545
Experience:  12 years at a Ford/Lincoln Mercury and Jaguar dealer as technician and shop foreman.
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2002 Jag S-type 3.0. No HEAT.

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2002 Jag S-type 3.0. No HEAT. Not from any vent, not on any setting. A/C works fine. Heater core is not clogged. Already flushed it. Both lines going into, as well as the one coming out of the heater core are hot. Engine temp never goes past normal, so I don't think it would be a thermostat problem. Since everything else works fine, the DCCV doesn't seem likely either. Could it be a vent actuator or something like that? Please help, will gladly pay. I don't have any electrical testing equipment, but could get somebody to help me with that if necessary.

Hello and welcome to


Based on your description you have a partially stuck heater control valve. This is the only component that controls the heat. There is no temp actuator. Locate the valve and disconnect it to see if the heat starts to work. If it does then it is an electrical problem with the control module or wiring. If it stays cold then it is usually a mechanical problem with the valve.

Customer: replied 6 years ago.
It's really hard to see the connection. Do you know off hand if there is something to press or lift to release the connection?
Instead of doing that remove fuse #1 (10 amp) in the engine compartment fuse box. There is a red locking tab on the connector making it difficult to remove.
Customer: replied 6 years ago.
Ok. The only difference with the fuse out is instead of blowing ice cold air, it just blew outside temperature air, but no heat at all. It sounds like I need to replace the DCCV. One last question. Any reason not to buy the Lincoln LS DCCV at 1/3 the price of the Jag DCCV? I really appreciate your help, and will push the ACCEPT ANSWER button upon your reply!
Yes it is most likely a problem with the valve. You can use a Lincoln LS valve but if you wanted to use a Jag part recommend,,,,,, or as they all specialize in discounted Jag parts.
Richard and 2 other Jaguar Specialists are ready to help you
Customer: replied 6 years ago.

UPDATE: Thanks to your help, was able to replace the DCCV today. Unfortunately, still no heat. The old one was stuck in the shut position, so I thought we were going to be good with the new one.

One thing that may help: I removed the #1 fuse to see if that made a difference. It did not. However, I did notice that when I removed the fuse, I could clearly hear the heater valve either open or close. Then, when replacing the fuse, I could hear it again.


It doesn't make sense to me. All three of those lines coming out of the DCCV are HOT. The heater core is not clogged. Could a bad climate control module be the culprit? Everything else works fine, just can't get any hot air.

By disconnecting the fuse we eliminate the module as the problem. The way the system works is the module will pulse the valve closed for a/c. If the valve loses power or signal it will default to fully open. If the fuse is removed but the air is still cool then this is not a module problem. It is either a faulty valve or clogged core. I know you said the hoses are hot but do you have good flow.
Customer: replied 6 years ago.
I am absolutely perplexed, here. The heater valve opens with the new DCCV.
I hooked up a garden hose to each of the heater core lines to make sure there was good flow. No restriction from any line.
All three lines are hot, which tells me that hot coolant is getting into the core. How is it possible to have no heat if the hot coolant is getting into the core? Do I need to take it in to the shop to get tested?
Could it be possible that one of the hoses going to the valve was reversed?
Customer: replied 6 years ago.
I suppose it is possible. I was surprised to see that the lower hose on the heater valve leads to the upper right on the heater core. Is that right?

Go back to the valve and the heater core. If you look on the heater core side the larger diameter hose is the top outer which is the return. The driver side is the top inner and the passenger side is the bottom. We should also make sure there is no air trapped in the system. There is a bleeder screw located in the rubber hose hooked to the coolant tank.

Customer: replied 6 years ago.
Routing of the hoses is correct.

I opened the bleeder screw with the engine hot, heat on full blast. solid stream of coolant came out. Is there a procedure for bleeding the system?