Is200 Alarm Problem

[CrocodileHunter]

Hello

I am new to the forum, I have only had my IS for a few months but can honestly say it is the best car I have ever owned!

I do have a small problem with it that was there when I bought the car and that is that the standard alarm seems to go off when it feels like it?

I have been getting around the problem by locking the car with the switch on the drivers door and the key so the alarm doesn't arm itself but I really want to try and get to the bottom of it.

Doing a bit of searching on the web seems to suggest that the interior sensor is a common fault on these? The guy I bought the car off said he changed the sensor but it didn't fix the problem? I have disconnected it now and the problem is still there?

I then thought that maybe the bonnet catch switch could be causing the problem but even with this disconnected it still happens?

As it seems to be very random as to how long after locking the car up it happens I think it could be an alarm wire shorting out somewhere? I did read somewhere that the wiring above the headlining has been known to do this but personally I think this is a long shot and don't really want to take the headlining down to find nothing wrong.

All the doors seem to operate the interior light ok so I assume the switches are all good?

I have not yet checked the boot switch which I should really do, but does anybody have any other ideas on what it could be?

The car is a late 2001 IS200 which I believe is the facelift model as it has isofix brackets the back.

Any tips would be greatly appreciated!

cheers

[scudney]

Try changing the Battery in the key fob and you maybe pleasantly surprised

[CrocodileHunter]

Really????

Have you seen this before then?

I don't understand how but will give it a go!

Cheers :)

[scudney]

Yes,try it hopefully should work,years ago when I had my first IS 200,the alarm all of a sudden started randomly going off for no apparent reason,got fob Battery changed (on advise) and didn't happen again,so worth a try.

[CrocodileHunter]

Ok, I put a new Battery in the key a for a couple of days all seemed fine! I couldn't actually believe it. Never had it gone that long without playing up, although I didn't trust it overnight just yet but for hours on end during the day it was all good.

However yesterday in the hard rain it went off twice, just as I was getting more convenient it was actually sorted.

Suppose this could just be coincidence but rain to me means dampness shorting something out.

Maybe the wiring in the roof is as fault too?

[scudney]

Okay try disconnecting and then reconnecting the cars Battery and see if that stops it if not you maybe need an auto electrician

[CrocodileHunter]

Ok I shall try this and keep my fingers crossed!

Thanks for your help on this

[CrocodileHunter]

I'd forgotten about this thread!

I tried disconnecting the Battery but that has not fixed the problem.

One thing I have noticed is that it only seems to go off in the rain now? Before changing the Battery in the key it was alot more temperamental than that so thinking this is a separate problem?

Can anyone recommend a good place to take the car in the Bedfordshire area? Or any good auto electricians?

[scudney]

Hi sorry to hear you haven't totally cured your alarm problem

[CrocodileHunter]

You know at first I really thought we had it sorted, but never mind! Thanks for your suggestions, it did help alot.

I'd still like to get to the bottom of it but I am not going to spend loads of money doing it. I am comfortable working on cars but with this I have run out of ideas with.

It is clearly getting a volt drop from somewhere but I don't know where?