My Jag S Type locks the doors by it's self.

Hello Eric Lovins,

Your ignition switch goes directly to your BODY module and the engine control module... (with only a RELAY) in the mix...
for "starting purposes only"

My experience with Jaguars (magnificent vehicles) has
taught me to FIRST SUSPECT RELAYS... (easy access the switches (really hard to reach... If you plan on keeping the car
(mine being the last V12 Convertible they built)... I keep spare relays... HOWEVER...

Control of the running (or not running) seems to be the
Ignition control directly from the steering column to the BCM.

Logically your Ignition switch (highly used & difficult to get to) should be most suspect... (there are also high risk of triggering logic circuits with RESULTING AIR BAG DEPLOYMENT (EXPLOSIVE FORCE))... Use of care and full knowledge
is advised here...!!

http://www.ebay.com/itm/707-Jaguar-XK8-97-05-ignition-lid-trunk-door-lock-locks-cylinder-with-key-HH-/320858591370?hash=item4ab4a9908a:g:q88AAOxy-j9SRa1w&vxp=mtr

I have the Factory Service Manuals for MY '95 XJS...
They are impressively expensive... but WERE cheaper
(NEW, PAPER) than a single "visit" to one of my
neighborhood JAGUAR DEALERS...
(assuming all thing go well... they usually don't).

While the Factory Service Manuals are collectors items themselves you might remain in convinced of their inherent value... you can use the FREE data base at BBB Industries
website... (registration required)

(also see Jag Lovers site below (very bottom)).

I found no Technical Service Bulletins on your ignition lock
(a good thing)...
but in my car it would be very simple to eliminate DOWNSTREAM electronics... simply by removing the wire from the ignition (the engine should stop)

You can then confidently pursue that wire into your ignition lock...

My vintage vehicle has no PATS (passive anti-theft system) keys... but I will assure your life will be happier if you make SURE you have all the required keys & fobs BEFORE you get into the lock.

More Information for STANDARD MOTOR PRODUCTS LX1013

More Information for STANDARD MOTOR PRODUCTS US1076

Start relay (always good to have SPARES)
http://www.rockauto.com/en/catalog/jaguar,2001,xj8,4.0l+v8,1440757,electrical-switch+&+relay,ignition+starter+relay,3804

Jag lovers the Jaguar Enthusiasts premier Internet site

Might be some obstruction in the lock cylinder itself.

Insert your key in the ignition and turn it on and off. Push the Arm button until you hear it lock. That does the trick for me always. I own a 02 jag myself.

It may not be the battery, it may be the ignition switch. There is a switch within the key barrel if this switch gets dirty the remote lock, I have a 2004 model. Squirt some WD40 into the key barrel and turn the key a few time to shift the dirt, then try the remote. The switch is design not to lock the doors accidently, so the switch has to closed, when you take the key out of the barrel.

This is accomplished through the use of door lock actuators. If it is only 1 door, it is most likely that the door lock actuator has failed. It is not uncommon. These can be purchased through Ford or Jaguar and is something you can do yourself depending on your ability.

door jamb switch

hi, try disconecting the battery for a couple of hours and try again but make sure you have your stereo code. if this does not work your key fob may be out cync with your ecu and will require reprograming it is easy on x type , you can do it your self ,you can find the instructions in jag forums or ebay for 1.99

yes.... my friend has a jag s type and he said the horn sounds when he locks the doors

It could be the selenoid lock it self , which is located at he front of the Selector. You might need to remove the selector and test it if it is working properly. As it should be working for safety reasons