Hi - 2004 XJR Supercharged - my first Jag. I love it. Even when I hate it. I've done many repairs thanks to this forum including air shock replacement and headlight change. This one is beyond me and I could really use some help.
A few weeks ago I noticed my fan was running after I shut the car off. Thought it was just due to heat. That continued for a days, then while driving, the needles all dropped on the gauges and all the indicator lights came on the dash. Pulled over, shut her down, gave it a few minutes and started back up with no issue. It happened again and I took it to the shop. The guy said that the battery is bad. The battery is less than 3 and have had it tested multiple times with no indication that it's bad, though I'm sure it is constantly being drained by the running fan.
I've bought another battery to test the theory, but am concerned that it is something else causing the issue. Has anyone run into this?
Photo of the dash upon the last "shut down" is attached. Please note that the engine is still running and the car driving when the dash does this. It does not say "limp home", only things like "cruise not available, dsc not available, low brake fluid, etc"

 

Same answer as here

https://www.jaguarforums.com/forum/x...1/#post1501322

Check the earths behind the headlamps, on the ABS and IC then look at the pins in the TSB

The IC goes crazy, exactly what you describe when it looses data

Its most likely a dodgy pin or the wire. If you replace the pins and it reoccurs run a new wire on new pins

Cheers
34by151

 

Hi cleve,

That's a weird set of symptoms for sure. Regarding the fans running after the engine is shut off, do you mean they run forever, or they just run for several minutes? It's been quite a hot and humid summer in Nashville, so perhaps they're just having to run longer before the coolant temperature falls to the point where the temperature switch shuts them off? Have you checked your coolant level?

Your instrument cluster symptoms sound like those described in this TSB:

http://www.jagrepair.com/images/TSB/...%20Cluster.pdf


Cheers,

Don

 

You also need to check out your cooling system
I dont think your IC issue is related to the fan

For the Fan check the plugs near the foglamp as the small one of the two may be unplugged causing the fan to run full

Also check the fan status with the engine cold and the coolant levels

Cheers
34by151

 

Also check fan relay friend of mine had similar fault turned out to be the relay was at fault

 

Ditto Clifton, above

If contacts stuck in fan relay, could be running your battery down, which could engender the secondary issues

 

Thanks for the replies and sorry for my delayed response. This weekend i am going to try to address the issues and report back.
Based on this collective knowledge, I'm going to tackle as two separate issues. Will check the fan relay first to see if that gets "easily" resolved, then will work through the bulletin on the IC.
Just for clarification, the fan does not 'always' run as i previously stated - it runs for a few minutes after the engine is off and key removed. Also, when the car is on, the fan runs considerably louder than usual, almost as though it was full speed.
My coolant levels are solid and the temp gauge has been steady in the mid-range.
I may PM a few of you guys for guidance if you don't mind.

 

Have you checked the earths behind the headlamps yet ? These fail by corrosion and cause all sorts of trouble.

 

I just did. They were tight and in good shape. Now I'm looking for the ABS earth as well as the connection behind the fog lamps.

 

You may just have some air in the cooling system that needs to be bled out as your fans are tuning off. Do the simple things first

The IC issue will be a separate matter

Cheers
34by151

 

cleve,

Note that the ground studs, wire ring/eyelet terminals and nuts are all made of aluminum, so the corrosion that resists current flow is not typical rust but a very thin coat (4 nanometers thin) of aluminum oxide which occurs naturally when aluminum is exposed to atmospheric oxygen. This thin layer appears as a whitish residue. Aluminum oxide is an electrical insulator and adds resistance to electrical circuits, some of which are very sensitive to voltage and current changes.

Unless your grounds have been cleaned within the past couple of years it is almost certain that they suffer from this condition. It's a good practice to periodically disassemble the ground components, clean the nut mating surface and inner threads, the stud threads, and the wire terminals. I use a brass brush and zero-residue electrical contact cleaner spray. Allow to dry for several minutes, then reinstall.

Do not use sandpaper because it leaves fine scratches that actually promote the formation of aluminum oxide, and a wire brush is better for cleaning the stud threads anyway.

The torque specification for the nut is a very low 6.5 ft. lbs., or just a little more than hand tight. Several members have discovered how easy it is to pop the stud right off of the body by overtightening the nut, so take it easy.

The post at the link below and the rest of the thread offers more info on cleaning the grounds:

https://www.jaguarforums.com/forum/x...2/#post1156791

Cheers,

Don

 

I've not been able to locate the fan relay. Any chance you (hisport, clifton94) can direct me to the relay?
Also, Don B, thanks for the info on the corrosion and torque. It was too late for one of the studs as it popped off at 5lbs.
Also looking for instructions or a TSB on bleeding the coolant system.
ANY help is appreciated.

 

The fuse is in the engine compartment so if there is a relay I would guess it's in there I think there is four does the fan stop if you pull the fuse

 

Update for those who are curious:
I've cleaned the grounds, bled the cooling sys, cleaned the connections for the fan and FCM. This has resulted in the fan running much quieter and not at full speed as it was previously. Also, it has only continued to run once or twice after turning off the car.

I have not yet gone through the TSB to clean the pins for the IC, but will try that this coming weekend. Hopefully, cleaning the grounds has helped the issue.

Thank you to all for the responses and assistance. Your knowledge is greatly appreciated.

 

cleve,

Good work! When you get ready to clean the ECM connector pins you will need a 5-point security Torx bit to release the connector. These bits are like typical 6-point Torx bits, but have only 5 lobes, plus a hole in the center to allow the bit to fit over a pin in the center of the screw that holds the connector. I bought a set from an eBay seller for about $20. Expect to find some leaves and seeds and other debris accumulated over the drain below the ECM. Clean all that out and run a length of string trimmer line or similar down the drain to ensure that it's clear.

Regarding some of your relay and fuse questions, the reference you need is the Electrical Guide, which can be downloaded free at this link, courtesy of our forum member Gus:

http://www.jagrepair.com/images/Elec...al%20Guide.pdf

The page before each schematic contains a list of all the components involved in that particular circuit and a brief description of its location.

Cheers,

Don

 

Well done!

Suggest replace the fan relay (and the air compressor relay, while you're at it). Cheap, and then no worries