The other day I was using multimeter to find power supply for my LED headlights conversion. I was searching the light switch circuit, and my brain wasn't working properly at the time, somehow I caused a short on the board. I've reset the car several times by now, anyway, since that short, the dashboard backlight is ON all the time, even when the car is locked. If I unplug the circuit, they are off. And I believe it caused another problem with alarm.
It used to be: press once, locks doors. Press second time, 2 bleeps. Press third time: switches headlights on for 30 seconds. But now I press the button once, it locks doors, press it second time and switches the headlights on for 30 seconds and after that the alarm goes mental! I think there's no other option for me but to get a new circuit board for the light switches, right?

 

Ordered new switch circuit yesterday, I'll know a bit more when it arrives... Hope it'll get it sorted...

 

right, the little circuit with switches arrived, I replaced it and the dashboard backlight is OFF now, so at least that damn thing won't be draining the battery any more But the locking is still not as it used to be. It still doesn't do any bleeps when I press the button on remote twice, it just switches the headlights on for 30 seconds... But I checked and the alarm itself works, as I sat in the car and opened the door when everything was locked with remote... Eh, only week until the deadline and I haven't got a clue!!!

 

Maybe when you did the reset, you disabled the beeping on locking?

I think with my S Type and using IDS, I can configure the horn to chirp on the second push of the remote lock button, or disable this feature.

If you had IDS you could check and possibly program the car to be the way you want it. If you don't have IDS, then maybe it means a trip to the dealer.

Hopefully a tech will chime in and provide good news for you. Sorry if I made it worse.

 

Oh, there's no time nor money for trip to dealer now, next week it's getting its heavy *** on the boat and sailing away... But hey, as long as the actual alarm works (which it does) I'm sort of happy :-/

 

Lets continue the lights nightmare. I replaced the circuit board with light switches and everything was fine for some time. But then I started putting the front door panels back on, installed the stereo and guess what! The backlight was back ON!!!!

Oh, dear... I nearly started crying... After having a conversation with Tim yesterday, we agreed it might be a good idea just put a switch somewhere in line with a dimmer, located on the steering wheel column. So I took it apart and found 5 cables coming out of the dimmer switch. Checked voltage, only one of them was getting around 10v and 3 of them were showing about 3v... but that's not very important right now. I unplugged the dimmer and... THE BACKLIGHT WAS STILL ON!!! So placing switch on any of those cables was out of the question! Went back to the search near the circuit board. If I disconnect it, the backlight is off and alarm goes back to normal. So I checked (more carefully this time) which cables were giving power supply to the circuit board. I'v found 3, I tried disconnecting one, then reconnecting it and trying the next one. Well, none of them did the trick. So I just cut off all the cables, plugged spare plug with longer wires into the circuit board and started reconnecting cables one by one with those quick connectors with screws. And I've found that it didn't matter that much which cables were disconnected (of the ones that were supposed to carry the power FROM the circuit), as long as one was off. So I went ahead with brown one I think, I placed the switch in the plastic cover underneath the circuit board and put everything back together. And the funny thing now: dashboard backlight is off, alram is back to normal, but if I switch the light on, everything works normal, including the dashboard backlight. So I haven't got a clue what it is that I disconnected, but it did the trick! Confusing as hell!!!

 

I would hazard a guess that you fried a diode in the instrument module. I don't remember what it looks like, but most of the Jag modules can be disassembled and repaired.
I bet the dealer will whack you good for a instrument module. Better to find one at a breaker.

 

too late for messing around with that mate, in 2 days car is going to be on the way to Port of Tilbury and then getting its wheels on a boat, and then I'll see it 20 days later But as long as it works, I'm happy, I just need it for that one road trip