Your meter is likely fine. Wouldn't hurt to get a mechanic's view any way.

 

That I will do, first part of the new week.


Thanks again to everyone for the input. This will be overcome, a minor bump in the road. I love driving this car, and will get it going right again, no doubt.

 

Finally got a break in the rainy weather and ran the XKR over to my regular mechanic for a load test on the battery. Results were, in his words "somewhat marginal".


So I don't doubt a new battery is needed. Maybe not for a normal car, but for a Jag, yes .


But as he and I agreed, a weak battery does not cause a fuse to blow, and that's where this saga began...the 5 amp fuse for the instrument pack.


And why on earth should shutting down the ignition and removing the key close down all other functions but leave the instrument pack alive???

 

Wow!!! Burnham, you certainly have a teaser!
Not "sage advice" from me . . . but I am starting to wonder if some of your issues are not directly related, but inter-related, via an unlikely source. The blown Fuse#18 still troubles me also, but more so, the continued IC operation/illumination after the ignition key is removed. Can I first suggest a plan, then my reasons -

1. Replace battery with new fully charged and tested unit;
2. Read, record and clear any codes;
3. Repeat ignition key start then shutdown cycle - with particular and detailed record of precise shutdown/key removal point of fault - ie is it when key moves back 1 position, or 2 to off, or only when key is removed?

Reasons include the obvious - your mechanic's test and verdict of your existing battery - and my growing concern that perhaps the blown fuse, but certainly continued operation once key is removed, may both be issues linked to a failing/failed ignition switch itself. Being a mechanical switch subject to wear, it is a possible, even if unlikely, culprit.

Best wishes
Ken

 

Thanks for the reply, Ken.


Can't argue against the battery, for obvious reasons.
I don't have a code reader, but suppose I might be able to again impose on my regular mechanic for that.
The ignition switch had given absolutely no indications of faulty operation prior. I can get no change in behavior with adding some lubrication, or physically manipulating the switch and key during any of the start, run, or shutdown processes. The fault is only NOT present when the ignition is in the run position. Otherwise, unless I remove that #18 fuse, the instrument pack remains powered and the message window cycles continuously through what I believe are all fault messages it is capable of. I may be wrong on that last, since I'm not sure what all those might be . I guess I might be able to check that against my owners manual...

 

According to the wiring diagram, fuse #18 in the driver's fuse box is the main power to the major instrument pack. Fuse #14 (10A) is the ignition switched power to the major instrument pack - as well as other places- (see Fig 08.1). It might be interesting to see if removing fuse #14 makes a difference. Then, if it does, to see if the both sides of that fuse have power with the ignition key out. There is a relay, apparently also in the driver's side fuse box (see FIG 01.1), which switches the main power to become the ignition switched power. If that relay is stuck energized or stuck closed, it could cause ignition switched power to be present at the major instrument pack all the time. If ignition switched power changes with the key at the major instrument pack OK, then this might indicate an internal short at the cluster.

 

I'll do some checking, thanks very much.

 

OK...pulling that #14 10A fuse made no difference.

 

I'm beginning to get discouraged.


Anyway, ordered a new battery and will pick it up and install either this afternoon, or more likely tomorrow as the weather is supposed to be dry Saturday.

 

New battery installed, no drama .


But nothing changed with the whacko instrument pack.


I reckon I'm out of things to try on my own, unless anyone else has a suggestion.


I hate to give up on fixing it myself, but may well have to take it in to a pro, I fear.

 

Only one other suggestion, which you may have already covered. You suspect that something maybe shorted out in the instrument pack and the blown fuse implies that, but maybe it's not the area mentioned in the TSB.
So, besides the area mentioned in the TSB, did you check the rest of the major instrument pack circuit board for solder migration, rubbed away tracks, burns or burned-out tracks? The other side of the board maybe, although maybe that's not easy to get to. Is there anything visible on the backplate, discoloration or signs of rubbing, that could give a clue, maybe, of a different area of the board that could be involved?

 

Paul, I checked the circuit board that is exposed when the back plate is removed very carefully; indeed, I used a magnifying glass ...you and I are thinking alike in this. But I found absolutely nothing to indicate a short or excess heat or friction on either the circuit board or the inside of the back plate. I went no deeper into the instrument pack than that.

 

For grins, remove fuse 6 on drivers side and see if it has any affect, this goes to the key transponder module, I think this is for remote ops from key but since you are out of ideas it's easy to do.
Otherwise here are some diags from the jtis you might consider:

CHECK THE IGNITION SWITCHED GROUND (1) TO THE BPM
Turn the ignition switch to the ON position.Measure the resistance between FC14, pin 41, (RW) and GROUND.
Is the resistance greater than 5 ohms? REPAIR the high resistance circuit. This circuit includes the ignition switch. For additional information, refer to the wiring diagrams. Test the system for normal operation.

CHECK THE IGNITION SWITCHED GROUND (2) TO THE BPM
Measure the resistance between FC14, pin 15, (WU) and GROUND.
Is the resistance greater than 5 ohms?
REPAIR the high resistance circuit. This circuit includes the ignition switch. For additional information, refer to the wiring diagrams. Test the system for normal operation.

CHECK THE ACCESSORY SWITCHED GROUND TO THE BPM
Turn the ignition switch to the ACC position. Measure the resistance between FC14, pin 32, (WR) and GROUND.
Is the resistance greater than 5 ohms? REPAIR the high resistance circuit. This circuit includes the ignition switch. For additional information, refer to the wiring diagrams. Test the system for normal operation.

 

You mentioned lots of rain lately. Any chance moisture is either puddled in your boot around the security module...or has any gotten into the power distribution fuse box under the bonnet? My lid has a broken snap on it, and I'm always worried something is going to get into it one of these days. If I.had the wiring diagram for your blown fuse, I'd trace it all the way back to the battery, just to make sure.

 

Have you test it??????

 

Resolved this issue by replacing the main instrument pack with a used one I found on Ebay. Had the good fortune to find one with nearly the exact same mileage. I'm back up and operational .


It was a simple swap over, no drama. If anyone is interested in the process, let me know and I can write it up...nothing special so long as one remembers "it's a Jaguar".


Thanks all for your suggestions. They contributed to diagnosing the likeliest issue and I appreciate it.

 

As I admitted earlier, Burnham . . . a real brain teaser. This is the third failed IC pack I am aware of . . . each exhibiting wildly different symptoms . . . each somewhat short of complete failure.

Congratulations on your dogged determination, and I am delighted you persisted to achieve a complete solution. Thanks also, Burnham, for sharing that solution. Well done, that man!

Cheers,

Ken

 

Hi Burnham,

I'm having some electrical problems of my own, right now! Did you get a diagnosis and fix - and what was the result?

 

Diddion...see my post #36. All diagnosis was by me with help from members here. I did the replacement myself.


So far, all is well with my repair. I've driven it about 1500 miles since then with no issues.

 

Hi Burnham. I've received warnings from forum members, that swapping out the IP may cause the car to go ino anti-theft mode, which immobilises it. I take it you didn't experiene this particular problem?