Key won't turn unless battery reconnected

Sounds like your steering column anti theft control module has failed, do you here a whirr and a click coming from the steering column when you put the key in the ignition?, if not then the module, or the solenoid that retracts the steering column lock pawl has died, or jammed up. You can electically bypass it by pulling fuse 18 and installing a toggle switch and using it to cycle power to the control module every time you want to start the vehicle but if the column is locked you won't be able to steer the vehicle. Its not a cheap fix if you need a new control module.

I don't hear whirr from the steering column. So, if they solenoid is dead, why removing fuse 18 and placing it again allows the key to turn?

Also, what is the steering column for L322 2007 HSE Jaguar engine? is it QMB501270?

Can I replace the selenoid alone? what is the part number for it?

Sorry, too many question, but I'm trying to understand before the dealer rips me off.

Theres about a billion threads on here about the steering column issue, but here a youtube video that explains it (there are also a ton of different ones on there as well)

https://www.youtube.com/watch?v=t_nj4Xscxto

I have a similar problem in that the key won't turn on my 2008 3.6 TDV8. It happens intermittently when I have my caravan connected. The problem is resolved by disconnecting the caravsn electrics. I suspect that the problem is due to a voltage drop.
It might be worth changing your battery.

Im in Houston, with a 2005 HSE that did this stunt July 3rd, 2018. Turns out there is a permanent fix. They dont make the upper steering column for these trucks anymore, ( good !!) and if you could get them, they are $4500. I got by for the meanwhile with Fuse 18, and leaving the key in as I could. ( the car will start after re setting the Immoblizer with the fuse 18 thing) and you can LEAVE THE KEY IN and it will start every time. Pull the key, and you start over again.
I decided to call Independent garages, and found BRitish Unlimited, in the Woodlands, TX north of Houston. They re wired the column and center console components, and now its FIXED. $1075. Worth it all. Its not easy, and these independents see this problem all the time.
British Unlimited, ( Steven, or Luis ) 281-292-8022
Good Luck [email protected]!