Hello folks - question for you!

I have a 2004 4.2L V8 S-type and Fuse 32 has started blowing.

Here's whats happening - The air conditioning in the car still works great, however, if I trying changing the temperature away from Lo, the fuse blows. If I change the temp to say 18 and replace the fuse, as long as I don't try to change from 18, the fuse is fine. It's always when I try adjusting the temperature. When the fuse blows the blower becomes a hot blast furnace.

I see that Fuse 32 looks after the DCCV and an aux coolant pump, but I'm trying to pinpoint where the problem lies in the system. I'm leaning towards the issue being a faulty DCCV but can anyone confirm?

I'd like to pinpoint the problem before taking it into the shop and spending $$$ on a mechanic doing a bunch of tests just to find out it's the DCCV.

Thanks in advance guys!
Rob

 

The DCCV is indeed a likely suspect, but so is the climate control module behind the dash. It may have one or more burnt traces on its circuit board. In order to find out, you will need to remove and inspect it carefully. Any burnt traces should be fairly obvious....

 

The DCCV's are very common in the S-Type to short. Particularly with the 4.2, as the coolant expansion tank sits directly above it. Make sure this isn't leaking from the small bleeder pipe that sits below the bleed screw, if it is leaking, it goes straight onto the connector for the DCCV. You will also need to check the circuit board of the Climate Control module as Jon stated, this is usually the weak spot that gets taken out when the DCCV shorts. This can easily be repaired without having to buy a new one. You should also be able to sort a new valve through the forum, as there are a few companies affiliated, without buying genuine.

 

Since the ducts blows hot after the fuse opens, that at least tells us the DCCV is not seized or clogged. The default position (no power) is spring-loaded to the open position for full heat. Check to make sure you are getting heat on both sides of the cabin after the fuse blows. If only one side is hot, that means one side of the DCCV has failed.

And if you're getting good AC at some point, that tells us the DCCV is at least responding somewhat to close when commanded.

Re: "Adjusting the temperature". Does the fuse blow whether raising or lowering the temperature setting? When the temperature setting is raised, power is removed (or reduced) to the DCCV. I would think the fuse would only blow when the temperature setting is lowered, meaning more current to the DCCV.

The DCCV is still your most likely culprit, but there is one more thing to check. Disable the auxiliary coolant pump by removing relay R7 in the front power distribution box. I'm not sure of the exact interface, but it's possible the pump is commanded on when the temperature setting is raised. That would be quick and easy to rule out. Be careful because the pump is also part of the overheat protection for the engine, but you should be okay for a quick test run.

 

Thats all you got for us "Hello folks"! Sheesh Rob, where the heck have you been? How have you been? Hows the S TYpe other than you need to replace your DCCV


Welcome back buddy!

 

You can check the operation of the DCCV here, detailed in post #2:

https://www.jaguarforums.com/forum/s...ol-how-185002/


This link has details on how to check the DCCV amp draw:

DIY: Diagnose It Yourself - JaguarClimateControl.com

 

Rob, what did you figure out?

 

Remember that the DCCV AND the electric coolant pump are run by the same fuse. I had a bad climate control coolant pump fail and the DCCV had no power to close (open all the time).

The fuse was 'blown' and the pump motor had failed. The replacement fuse failed IMMEDIATELY and the pump motor was found to be the fault.

bob