You have the classic symptoms for a failed cross-car link harness that supplies power to the GECM in the lower LH "A" pillar. Here is the bulletin explaining the repair.

The white connector near the battery was used for a battery isolation device used to disconnect the battery during the boat trip here when the car was new. It's not used for anything and generally causes problems if it gets wet or mashed by the battery during a careless installation. Just tuck it up under the boot trim so it doesn't hang down and get into trouble.

Good luck!

 

Hi, I've joined up because I've got a 2003 S type where the battery drains itself.

About a month ago the passive alarm sounder was faulty, I changed the main battery just in case but the car eventually had a new sounder module and some high resistance wiring repaired at an independent Jaguar garage.

About a week later the battery went flat (the car only gets driven a few miles a day but it's been fine for the 2 years before!) so I took the new battery back and got a replacement under warranty.

I've tried the old battery and the new one, and after a week or so they go flat again. When I was working outside one evening and the car was parked, I thought I saw the headlights flash for a second. Since reading this thread it looks like I might have this issue, and damaging a connector while being clumsy changing the battery does sound a lot like me....

We drove the car for 200 miles on Friday, but on Monday morning the battery was flat again. I took the battery out and (for the first time doing this in daylight) I had a look for a mashed white connector but couldn't see it. Is this still fitted on 2003 cars, or is there another place to look?

 

Yes, that connector is still fitted to that car as well, though I have seen it be black instead of white a time or two.

It should be diagnosed as in the posted bulletin, also. It does not list later VIN numbers, but the condition can still occur on the later cars. The wire at Connector FH-59 pin 6 is probably a different color also, but the repair AND the listed link lead is valid for your car.

Good luck!

 

Thank you.

And black or white, I still can't find a connector anywhere near the battery. There's a large harness group which runs from the fusebox next to the spare tyre, but it's all wrapped up. Do I need to check for damage in there, or is the connector somewhere else?

As I'm a complete amateur at the S Type (although I had an XJ-S 15 years ago), where is the GECM? From the service bulletin it looks like that bypass lead is a spare part, do I need to order it from a dealer or can I make it up from some wire back when I re-wired my 1961 VW?

 

Here is one of those buggers.

The GECM is at the lower LH "A" pillar, behind the trim panel. Connector is a pain to get to, but it probably needs to be done. Find the Electrical Diagram elsewhere on the Forum, in it you will find connector illustrations to show you where the wire is exactly. The link harness goes clear across the car from the junction box at the RH "A" pillar.

Good luck!

 

Isn't this car well outside the VIN range for the bypass lead? Does it happen with a much bigger VIN range?

 

I have to join the crowd. Bought an '06 - 4.2. Love it. But having an issue with the lights coming on an staying on when in auto. Ran battery down once. When I lock the car, it beeps like everything is good, but the lights don't always go off. A friend said they were flashing off and on one time when I had turned the car off, but had not exited the car.

Also noticed it "searching" while driving around dusk - off and on, off and on.

Did not have these problems at all with my 03 3.0. Just left it in auto all the time.

Seems to me the control stick is suspect, as a couple of times I would rotate it a little, or back and forth and it would seem to work for a while.

I have not put a new battery in, so may try that. Any other ideas would be helpful.

I will update if I figure it out.

Thanks to all.

Jeff

 

I have the same problem with my 2006 Jaguar S Type. The lights flash on sometimes when the car is completely off and parked in my driveway. Does anyone know if I can just pull the fuse for the GECM (that useless cord in the trunk by the battery that is used for connecting a trailer, etc.) and that will fix the problem? Seems like an easier solution rather than doing what is required in the bulletin.

 

I'd think the stalk switch is the more likely culprit. Easy change, but a $240 part, if I recall correctly.

Here's a tip: https://www.jaguarforums.com/forum/s...solved-175596/

 

If you have the automatic headlight option, a defective solar sensor can make the lights come on after the ignition is turned off... at least mine did. A caveat though, if replacing the solar sensor, breakage of the "demister" (aka defroster) panel is a distinct possibility and this part is no longer supplied by Jaguar!

 

I have automatic headlights but I never use them. I always turn my lights on and off manually. When I shut the car off, I turn the lights to off. I will add that this problem with the headlights flashing on seems to occur when it is raining out. I'm just trying to figure out an easier way to fix this problem without doing what is required in the bulletin. I imagine Jaguar dealership would probably charge me around $3,000 to fix it since they just quoted me $220 for an oil change.

 

I would like to give it a shot at installing the forward harness bypass lead as per the Jaguar bulletin above but I dont quite understand exactly what to do based on the bulletin. Does anyone have any pictures or a YouTube video of the procedure? I could probably do it if I could see photos or a video. I think the dealership would charge me an insane amount of money if they do it. Thanks.

 

It's more likely the turn signal switch/stalk causing the problem. Do that first before bypassing parts of the wiring harness.
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The first step in executing the bulletin would be to read it through, at least once. If you start at the top and go left to right, as is the convention, you find pretty early on that you don't even need to complete the first step..that is, if we can place any confidence at all in your user name:
Model: MY 2000 S-Type
VIN: L00001-L70801

 

I don't think it is the signal stalk because this only happens when it rains. If it was the signal stalk, it would happen all the time. It doesn't. The bulletin says power drain and flashing of lights and that is exactly what I have. I have power drain (two dead batteries) and flashing lights. It sounds exactly like the bulletin describes. I'm located in Northern New Jersey if anyone is local and wants to help me out with this. Also, any pictures or videos on how to do the bypass would be helpful and appreciated. Thanks!