I know that my keyfob key is supposed to be able to open the trunk when the battery is dead, but it doesn't. I have 2 keyfob keys, and they work in the driver door, but not on the trunk lock.
So how can I recharge the battery without opening the trunk?

(My jumper cables are, of course, in the trunk.)

 

A lot of people have mentioned this across the forums and facebook groups, it is a common issue and can , in a lot of cases, be solved by spraying wd40 into the lock and manipulating the key gently until it works. Be patient and dont try too hard and risk breaking the key.
Lots of success stories after trying this .

 

The key is hardly ever used and so the trunk mechanism "sticks". Fiddle about some more. I tested my key the other week, and it took a bit of effort, jiggling, whatever.

 

Do you turn the key clockwise or counter-clockwise to open the trunk?

 

Clockwise.
Also, pressing down heavily on the trunk may help. (just tried it)
There's quite a bit of slack movement before the key "hits" the mechanism in a clockwise direction.

 

I sprayed inside the lock with WD-40, and jiggled the key 50 times. It clicks when I turn it all the way clockwise, but the trunk won't open.

I've been trying to charge it for over an hour with a cigarette-lighter-to-cigarette-lighter charger, that's connected to a running Camry, but as yet it hasn't accumulated enough charge to do anything, such as open the trunk, or light a light.

I could go to the store and buy one of those batteries that plugs into a cig lighter to charge a car; that might work better. The charger I have has a non-standard plug that won't stay plugged into a cigarette lighter outlet unless I sit there the whole time and hold it, and it's too hot to sit in my car with the windows all rolled up because I can't roll them down because the power doesn't work.

Do Jaguar electronics prevent charging thru the cigarette lighter?

I think I really need to know where to put jumper cables in the trunk to charge the battery. Ground I can find, but I can't use a voltmeter to find 12v, and I don't want to experiment to try to discover what I should charge to 12v, as that would cause a short and probably damage whatever's providing the power.

 

The cigar lighters (this is a classy car) only operate with the ignition on ACC or more.

 

If you can get some jumper cables you can energize the car from the fuse box under the hood. Put the hot lead of the cables on either one of the metal leads of the 80 amp (I guess it’s a relay maybe) thing.

 

So... can I charge thru one if I turn the ignition key one "notch" clockwise?

 

I was just looking at Yellow Bandit's suggestion.
There's 12v on the studs of fuse F35 (with ignition off), in the front fuse box.

-------
"So... can I charge thru one if I turn the ignition key one "notch" clockwise?"
But your battery is dead, there's a relay at least.

 

Looking at the wiring diagram, 80 Amp fuse F35 connects (via other fuses) directly to the battery positive. The only relay in the way is the transit isolation relay, and that is removed at the dealer after delivery from the factory.
So you should be able to charge the battery from either end of F35 as the positive, and a good earth as the negative.

Pete M

 

To be clear, once you have cables connected to this point in the fuse box, you will be able to open the trunk using the button inside the car or on the trunk lid.

 

Thanks!! That worked.

 

What a great thread. My battery recently died in my 05 Super V8 - first time it happened I thought my key would not open the trunk as it would not immediately go in the key hole. After a firm push it did go in and the trunk did open right away.

After the battery died repeatedly (partly due to the bonnet open fault I was getting and the car alarm going off as well) the trunk key hole required more jiggling than previous and I had to push down on the trunk to get the trunk to pop open.

I solved the bonnet open fault by bypassing the switch by cutting and tying the wires together (the paper clip trick was preferred but this being my first DIY repair and not knowing the switch set up I cut the wires and taped them together). I am now a certified Jaguar technician.s

It turns out that the Die Hard battery in the car was 10 years old and had finally called it quits. It was replaced with an Interstate at a cost of 156 installed - discounted because the sales person had come into my golf shop a few days before and was impressed with my customer service. He said if I ever needed a battery to come see him. He was true to his word saving me 20 buck installation and 30 on the battery. Maybe that was regular price anyway but I was happy for the gesture.

All of this in the nick of time as my car alarm was keeping my neighbors and my wife up at night. Nothing like torches and pitchforks at 3AM to help hurry a job getting done.

But the fuse box trick is a great piece of knowledge. Thanks for the share.

Cheers
Mike D.

 

I have ingested the fuse box trick but I don't think I am

going to need it.

I have 'recently' installed' another Varta battery in the Jag.

The original only lasted 18 years- the last couple of years in another vehicle.

 

I keep my Sunday Queen on a permanent charger. Driving, even daily, does not necessarily keep it fully charged (just close to).

 

@Xeno
You should definitely investigate why your key doesn't work in the lock. I had the same issue and when I looked in there, the cable from the keyhole was actually disconnected from the trunk latch. It took me a few minutes to figure out how it was supposed to go, but it wasn't too hard. Note that the cable also enables the emergency release in case someone gets stuck inside the trunk, so it's also a safety issue.