Hi guys - my first post. After buttoning up after installing a new water pump I was ensuring I had all the electrical connectors re-connected. I spotted one behind the battery box and (initially) couldn't find where it goes. It's a two-lead female green & black connector. There appears to be a dummy/blank connecter on the back of the battery box so I put it there. What is this wire for?

 

I think it's for the brake vacuum booster pump that was on some early production cars.

 

I believe I finally found out a few days back during some random reading. This lead actually connected to some battery "isolator" that was in place during shipping. Once the vehicle makes it to the dealer, the isolator is removed and sent back to Jaguar and the connector becomes redundant. Does that sound plausible?

 

That is exactly what it is. ALL Jaguars since the late 1980's have Battery Isolation Devices and the ignition switch has a circuit to energize the relay. Once the devise is removed by the Selling Dealer, the device is removed and sent back to Jaguar for re-installation. The wire is tucked back into the harness or plugged into a non conductive harness connector and most people don't see it or care what it is used for. Some people ask questions about this terminal end and we get to talk about it on the internet!!!!!!!!!!!!!!!!!!!!!!!!

bob gauff

 

Mystery solved! Thanks Bob.

 

what is a battery isolator?
this wire has been bugging me for a while and the only answer until now was it plugs into the battery box but doesnt look like it does anything lol

 

Thanks Bob. Now I can sleep at night knowing I didn't screw something up.

 

OK everybody has agreed it's the battery isolator. I still think it's the vacuum pump lead. In the JTIS the wire colors for the pump are black and green (right Troopski?). If you look at the Technical Guide that's exactly where the control module was located.

I'd like to see a picture of the battery isolator with some wiring data before I jump on that wagon.

 

any questions? ready for FAQ?

 

Bravo sport30, Bravo.

many have wondered and a few have asked. Certainly worth a sticky in my books.

 

Correct Tony H - green/black. I took a picture of it but was not able to post it because I'm new... a need a few more posts to become worthy. Anyway Sport30 proves it out. Nice work... thanks.

 

Just a bit of left field thinking while i'm shut up in my hotel room...
I'm on the road for about 3 weeks per month, then home for one...
Would there be a benefit to the battery by enabling this isolation device while i'm away & would there be any serious drawbacks to the car's electrical/computer systems...
I'm looking at an ability to easily disengage the battery, not unbolt a ground & move it out of the way...
It would also keep the mileage down since i was silly enough to teach my three sons the joy of manual cars

Cheers
Gary

 

Put in a cut off switch someplace hidden. Mind you if any of my kids were to think about 'borrowing' Dads car.........Needless to say it's never come up.

 

But is there a way to insert a kill switch that would isolate the battery, that could use that circuit...
The Army trucks i work with have three kill switches that isolate the battery, great for extending the life of the batteries, but they're big/bulky affairs...

I keep getting out voted on killing my kids... lol

Cheers
Gary

 

Just take the keys with you.

 

If you plan on using a battery disconnect then plan on your radio needing the security code put back in and possible other modules that may need programming.

 

hi, I read your post and I'm glad u ask becouse I have seen that same wire and won't to know what it was and was afrade to ask . And that why we should read all of the posts so as to answers some or not all of our questions without asking the thanks same thing . Thanks again.
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Clair
2002 x-type owner

 

Old post, but this is what the battery isolators look like that come from Jaguar....
I ended up with a box of them after purchasing a lot of inventory from a dealer..

Cheers
David
EverydayXJ.com