Just purchased this XJS and was going over how everything works. Some how managed to set off the alarm and ended up disconnecting the battery to stop it. Boy...is it LOUD! I managed to meet some neighbors I didn't even know. The system seems to have a mind of it's own.
So, the question is...how can I disable the security system? The only fuse I could find was a 7.5 for the security ECU. Any Ideas?
Thanks...Jimmy

 

I wouldn't. ... learn how to use it properly. It should have a remote key fob that controls it.
It also controls the remote door locking and is handy when leaving the car at night by putting the headlights on....

 

Not sure if the '94 works like mine, but on the '90 XJS once you reconnect the battery you have to click the key fob 3 times to reset the system. Otherwise it will go off again.

 

I would keep the system except...the FOB works "sometimes" it will lock one door but not the other. (won't unlock sometimes) The trunk doesn't lock with FOB. The imobilizer doesn't like me at all since it kicks in whenever it has the notion, even without alarm. FOB has new battery.

I have studied the security manual, and its just not working the way the manual says. Not close. The only way I will be comfortable driving this car is to disable the security system. I would put in a valet switch, but that won't fix the intermittent locking problem. I prefer to forget the FOBs and just use the keys.

Thanks...Jimmy

 

Yep...that's the way it should work, but not mine. Reconnected battery, no alarm. Imobilizer wouldn't let car start. Disconnected battery, reconnected battery, car started! Shut off car, walked away from car, alarm went off. Disconnected battery. Now what? It's a shame because the car is in great condition, runs beautifully.

...Jimmy

 

Try reconnecting the battery and locking and unlocking the driver's door with the key.

That might also shut off the alarm. If it does, that will be temporary solution until you get other issues sorted.

Also, do you have a factory key fob?

The unlocking some, but not others, might be a relay or contact issue rather the fault of the key fob.

 

2 factory FOBs. One of the problems I had was the driver's door would not unlock even with the key. Until later when it started working again.???
...Jimmy

 

Right now the battery is connected and the car is quiet (fingers crossed). I will disconnect before bed since I don't trust it...Jimmy

 

I had similar problems with my 1996. I disconnected the security module after being locked out of the car. I don't wish to spend money on 20 year old electronic gadgets that I don't need in order to drive my car.
I disconnected the top module also so I can lower the 1/4 windows by themselves and lower and raise the top without having to apply the parking brake or have the car in park. Odd how we did without these 'conveniences' for almost 100 years.
Cheers, RagJag

 

Thanks for the reply RagJag. Exactly what needs to be disconnected at the security module? Mine is in the antenna area. I looked at disconnecting it, but wasn't sure what the side effects were. (if any?) I assume this will also disable the immobilizer?
Thanks again...Jimmy

 

read the sticky about how to program the alarm on the '93-'94. it is much different than the earlier ones..
https://www.jaguarforums.com/forum/x...ers-faq-33577/


Also the trunk lock has 3 positions. locked - unlocked - remote lock depends which way you turn the key.

 

Thanks malc4d...but, the security system has a mind of it's own so I don't want to use the FOBs. I can't have this car blasting away at me whenever it feels like it. I'll lock it manually if I can just get rid of the security system. There has to be an easy way to disable the system without major side effects.
...Jimmy

 

JayCee, keeping in mind that here may be differences in your 1994 and my 1996,
I unplugged the security module which is located in the right rear trunk. The module is mounted with one bolt at it's top. It is about 1" X 3" X 5 ". It is the only box there and is black. I haven't had any problems with getting into my car since unplugging it.
Luck, RagJag

 

Jimmy,

I understand your frustration but from your symptoms, I think there's more fault in the central locking actuators and control rods than there is in the security alarm system.

You've described keys sometimes not unlocking drivers door and passenger door and boot not locking. Those are typical symptoms of door lock rods ill-adjusted or actuators not functioning properly. That's further emphasised by the problems sometimes happening just with key actuation. If the fob locks or unlocks even one door then the fob and ecu are working properly and the fault lies with the locking system.

I would start by pulling the door cards and boot trim and then checking for play in the door rods, and also integrity in the wiring connections that conclude in the door and boot actuators. These are common XJS locking problems.

I think that once you've got the locking system working properly, you can then start to decide if you've really got an alarm system problem.

Good luck

Paul

 

I agree with you about the door mechanical items and will be working on cleaning and lubricating all. The car has been well taken care of, but it is older now and I plan on going over everything I can. I've already gotten many good ideas off this excellent Forum, like pull and clean all electrical connectors.
However...since I will never trust the alarm system, I will either disable it or put in a valet switch. Since I won't be using the FOBs the switch is probably a waste of time.
Thanks for your input...Jimmy

 

JayCee, did you find the lock module?
RagJag

 

This is what it looks like in the 1994. The only place to disconnect easily is all of those connectors on the side of the box. I'm a little nervous about that, since it would seem that it would cause some kind of issue elsewhere. I know yours worked out OK, but there may be differences with the 94. I still may go the valet switch route (or permanent ground) to get rid of the alarm.

Thanks for your input...Jim

 

JayCee,

If you follow this link:

http://www.jagrepair.com/images/Elec...Electrical.pdf

You'll see the entire electrical guide to your car, I believe the security system is one of the last sections. You'll be able to see the entire schematic, which should help you either sort the issues or know what you're disconnecting if you unplug the connectors going into the module.

Good luck.

 

JayCee, it does look different from my '96.
Cheers, RagJag

 

After looking at the electrical diagram (thanks Mac Allen) I have decided to just ground out the valet connector. There is just to many items associated with the security module, some of which don't seem to have much to do with security.
Thanks to everyone for the responses. I know that I will have a lot more questions as I start working on the car. Great Forum!
Thanks...Jimmy