This is an early RHD X350 3.5L, 2003 year, ( sold here in Australia as XJ350 ). Blower failed last week. Started checking with wiring diagram from CD. This suggests blower driven by blower control module ( BCM ) wth signals from climate control module ( CCM ). It says BCM is located above blower housing. I have an electronics business with lots of parts and test gear so this looked like a stroll in the park.

First problem is wire colours and wiring do not agree with CD. Downloaded workshop manual which does not mention BCM at all, so it probably does not exist. That suggests blower driven direct from CCM. Next problem is to find CCM. Workshop manual is confusing because although CCM is mentioned as being removed in a number of procedures there is not a specific procedure to remove CCM. Also RHD is not same as LHD, so hard to figure out location. I think I can see it on the right side of the CC main assembly, for a RHD car just to left of instrument cluster. Make sense ?
At least the under dash wiring is neat and tidy, most UnJaguar like.

 

Hi Richard

The attached may help.

 

Thanks, but so far cannot open those .pdf files.
Maybe because I am new member, forum does not allow it ?
This forum much more complicated to navigate than Jag-lovers where I usually exchange ideas and questions.
Really the only thing bugging me is to make sure the CCM on my RHD XJ350 is just to the left of the instrument cluster.
I have info on taking the cluster out then I should be able to get at it.

 

BEEN THERE, DONE THAT.

See if this helps:

https://www.jaguarforums.com/forum/x...er-quit-62390/

With the glove box down, you can see other components,

 

Don't take the center console apart. The fan control isn't there! It is behind the glove box! Climate control box is there behind the glove box too!

 

Thanks Glendoramike, your help appreciated.
Your car is surely LHD, mine is RHD. and I suspect that makes a difference.
Your reply suggests the blower is driven by a blower control module ( BCM ) which is what my circuit diagrams show. However, the wiring on my car does not agree with the diagrams on the CD.
Other information from a downloaded workshop manual suggests the blower driven direct from the climate control module ( CCM ), and does not mention a BCM.
I have a line drawing from the CD showing the BCM mounted above the duct which is above the blower, but it may not exist.
I can just see part of a module on the right side of the main climate control unit, just to the left of the instrument cluster. It has about 20/30 wires coming out of it and that suggests a CCM.
I have the choice of taking out the glove box on the passenger side to find a possible BCM, or the instrument cluster on the driver side to remove the CCM.
Glove box is easier, but may draw a blank. The blower is removed and works o.k. so far. Wish I knew for sure, that is the question !

 

With the fan out you can feel the cooling fins of the BCM. Removing the glove box doesn't take long and you don't have to disconnect any wires. Once the glove box is down you will see the BCM on top of the duct. Remember the heavy wires that go to the fan. You won't see them at the Climate Control Box. They go to and from the BCM.

The way it works is that the climate control tells the BCM how much current to send to the fan, which changes the speed.

When you look at the shop manual pages that I included, you will see that they cover both LHD and RHD.

 

Is the big silver box to the right of the air-con unit in this picture, the CCM?

http://dl.dropbox.com/u/38786586/Dash%20removed.jpg

 

On the left side of the picture on top of the duct; you will see wires going to a part that is above the fan location. That is the Blower Control Module. That is why I said to remove the glove box. You will see it then.

Yes, the silver box on the far left is the Climate Control box.

Remember, you don't have to disconnect any wires to lower the glove box down to get at the BCM. You can jump the two heavy wires at the BCM and the fan should run with the Climate Control in the ON position.

If you have a LHD version of the XJ8's the picture would be a mirror image of his picture.

I am going nuts trying to keep the LHD and RHD's right in the posts here!

 

Just in case: This is the BCM and it is the main cause of the blower (fan) not working:

 

Found blower module as described by Glendora Mike.
One trick to note, Mike said you can hang glove box down without disconnecting wires. True, but awkward for easy access.
You can pull all the bulb holders and wiring out easily. The 12V power socket is a problem, it has a connector with a retaining tang. The tang is underneath hard up against the shelf it sits in, you can't get at it.
I poked a slim screwdriver in the back of the connector and broke the tang.
Then you can take out the glove box. Tang is nice but not essential.

Opened up module, found it is linear amplifier. expected a switch mode control which is 99.9% of the market for such applications these days.
Checked blower is about 14A at 14V.
This means max power dissipation in module is 49W at half blower power.
Even with forced air cooling this is marginal for such a small heatsink.
The power FET in module has a thermal fuse of some type in its gate marked 114deg C. That was blown so FET could not turn on anyway.

Original FET Toshiba 2SK2313 which our regular suppliers only sell in lots of 3000.
Replaced with a device having higher current specs but TO220 industry standard package. Not as much heatsink area as Toshiba. It lasted 20 minutes then short circuited, no big surprise, which means I can have no blower or full blower which is better than previous no blower only.

Have bought small switch mode module rated 12V and 30A. In next few months will find time to try it. Switch mode does generate electrical noise which is not good in this car loaded with all kinds of electronic gadgets and data busses.
However there are ways to minimise this noise.

 

The reason that I wrote that the wiring to the glove box doesn't have to be disconnected is to simplify things. I only needed to replace the Blower Control Module and my way is quicker and easier than unplugging the connections. The fan can be tested without removing the glove box and I covered that in "Blower Quit." In the majority of cases, the fan quits because the BCM fails.

 

Fair comment Glendoramike.
If you ever have a problem in that area needing more work, quite possible as cars age,
getting the glove box out of the way is a big bonus. Removing that 12V power socket is essential and it took me a 30 minute struggle to deal with it. I can understand why it is the way it is, and if anybody at Jaguar noticed the difficulty they never bothered to come up with a simple fix.