Hello, I just inherited a 2009 XK with 35k original miles and it lives on a battery tender 100% of the time . Now , the battery is junk , tender will not do anything now . I heard about the sounder under the hood , on firewall somewhere , and some sort of battery in the front right fender well under the headlight ? I’m new to this . What should I disconnect to remedy this and where are these items located on my car ? Please , anyone’s info will be greatly appreciated . Thank you , Rick

 

If you have the vehicle's Owner's Manual, it contains the information on where to find the positive (+) remote terminal in the luggage compartment on page 188.

https://www.dropbox.com/s/vrrf3515ql...02009.pdf?dl=0

 

The sounder is located on the firewall, under the coolant reservoir. Lots of threads on it, just search this forum for ‘sounder’.

 

As others have stated the sounder is under the air bag as you look at the front of the car left hand side by the wind screen. remove the plastic cover and you will see it down below. To get at it, I had to remove the bonnet air bag, then the mount its attached to ( you need long extensions to get the botton 2 bolts), however I also had to unbolt the trigger sensor (black thing 2 x T30 bolts) to be able to get the mount out at its wire were not giving me enough room. This then allow me to unplug the air bag. I removed the sounder on the mounting bracket. I will add though even though ignition was off the battery was still connected. I have the red warnign on my dash about deployment and cannot clear using SDD so its either the sensor whihc triggered it or something else. So would advise disconencting battery so all systems have no power. Learn from my fail

 

Just a note to the OP, we don’t have bonnet airbags on this side of the pond. So you don’t have to deal with that.
Hitting a pedestrian will already do enough damage to the car, so why add airbags that will have be replaced, right?