Alarm Problems on 1996 TDi

**cabinetcrafts** · 29th Oct 2011, 11:54

Hi - I'm a complete newbie here so please forgive me if my terminology is a bit iffy!
12 months ago I bought my wife a 1996 Discovery 2.5l TDi.

Some months ago I replaced the 2 button remote battery as the alarm activated and the car was immobilised when we locked the car using the remote. As a precaution since then we have only locked the car using the key, opening with the remote.

Last week the alarm activated as we were driving down a narrow country road. As there was nowhere to stop safely we carried on but before we found a safe place to park (that wasn't someones driveway!) the alarm stopped. For a week the car performed flawlessly then yesterday as I was driving to the garage to fill up exactly the same thing happened. Again it seemed to reset or deactivate after about 20 minutes - although it felt like a lifetime

Final straw, last night as my wife parked outside the care home where she works it went off a third time. Again, despite her switching off the engine, pressing the remote and trying the key in the ignition switch and door the alarm continued for 20 minutes. (And she coudn't get the engine started again during this time either - it was immobilised) The residents were not amused! After 20 mins the car started first time.

Do you think this is likely to be something I can tackle myself with a limited set of tools or am I going to have to bite the bullet, take out a second mortgage and send the old girl off to be fixed? Can the alarm be temporarily disconnected until I can afford a more permanent solution?

**discool** · 29th Oct 2011, 13:44

Was it a full alarm ie. sounder and hazards flashing? if it was just the sounder then because it has it's own battery back-up you may have an iffy connection at the plug & socket at the rear of the sounder, if the sounder looses the hold off voltage from the vehicle battery the sounder will sounds assuming the battery is still ok after the 14 or so years, also check the vehicle battery connections.

If it was a full alarm then you do have a problem, probably with the ECU and there's no way to do temporarily disconnection after all it is a security system.

The immobilising system is 'passive' therefore will set without the key or fob being used, to remobilise the engine just keep the fob near the ignition switch when starting.

**cabinetcrafts** · 29th Oct 2011, 17:28

discool, thanks for your very quick reply. As far as I can remember all previous times the sounder went off but no hazards. As an update - twice this afternoon the alarm went off while the car was stationary on the driveway with no visible external influence to activate it. Definitely no hazards today. The second time I opened the bonnet and detached the plug from the back of the sounder - silence! I locked the car with the key as usual - the red light on dash flashed repeatedly in bursts for a few seconds and then settled down to a slow blink. I tried starting the car 10 mins later and it started fine. Does this mean I've a faulty sounder unit and can I simply continue to drive with it disconnected or is the alarm going off still but I just can't hear it now?

**discool** · 29th Oct 2011, 18:24

Could be a faulty sounder and the battery has had it as removing the plug the sounder should have sounded under it's own power supply, my sounders battery has been dead for as long as I can remember.

If the alarm is activated the the hazards will flash sounder or no sounder, so if you leave it unpluged and the indicators start flashing while your parked and the alarm set you will know it's a false alarm and need to find out why.

You could test the alarm, so reconnect the sounder and by either sitting inside and locking with the fob and when the led flashing settles down rattle your keys at the ultrasonic sensor, or lock from the outside leaving a window open and again rattle you keys inside the cab you will or should get a full alarm condition hazards and sounder even unlocking with a key will set off the alarm as the system is also voltage sensing.

**bananahead** · 29th Oct 2011, 21:41

Interesting that you had no hazards, but the sounder went off. If it was me i would just leave the sounder unplugged and carry on as normal... It is obviously an electrical fault, and those are the hardest to solve for a home mechanic (in my experience). IF the hazards arent coming on then you wont bother anyone else.

**cabinetcrafts** · 30th Oct 2011, 13:33

Update: This morning I opened the car with the key (didn't plug the sounder back in though as it was still quite early and didn't want to disturb the neighbours), sat in it and reset the alarm using the fob. waited until the red light settled down and then moved around as you suggested. Hey presto the hazards flashed and the engine was immobilised. Cancelled the alarm with the fob and the engine started first time.

I think I'll take bananaheads advice and leave the sounder unplugged and drive for a few days to see if there are any other false alarms. Is it worth seeing if I can pick up a replacement sounder from a breaker and swapping the current unit to see if it works or is it more likely the fault lies elesewhere in the electrics?

Thanks for all your advice - looks as though I may have saved myself an expensive trip to a dealer/specialist.

**discool** · 30th Oct 2011, 16:48

Leave the sounder unpluged for a couple of weeks and if no false alarms and it looks as if the problem has gone away for good then plug the sounder back in if the problem returns then go and get a replacement.
If there's still problem although the sounder is unpluged then start looking elsewhere to find out why.

Let us all know the outcome in 2 weeks time

**cabinetcrafts** · 30th Oct 2011, 23:04

Originally Posted by discool

Let us all know the outcome in 2 weeks time

will do - and thanks for your helpful advice

**cabinetcrafts** · 9th Nov 2011, 14:51

Well, been driving around now since my last post without any alarm problems

I may see if I can find a local breakers (Maidstone, Kent area) with a sounder and try replacing the current unit. Presumably if it then starts again I'll know it's a problem elsewhere in the electrics and just leave well alone?

On another matter, after the heavy rain last week I got in the car to find the fabric roof lining above the drivers seat was soaking wet and had detached. It looks a though the rubber seal at the top offside of the windscreeen has shrunk or perished sufficiently to leave a gap. Reading elsewhere on the forum I see a number of posts referring to Sikaflex 221. Is it a simple job simply to clean up round the seal and frame and inject a decent amount of Sikaflex to fill the gap or do I need to do any other form of preparation first?

**discool** · 9th Nov 2011, 16:58

I only know of a LR breaker just outside Canterbury they also sell suff on 'eBay'. Your windscreen is bonded that won't mean it doesn't leak but the rubber u see is just trim but Sikaflex 221 is just the job for sealing any holes.
You don't have sunroof then, as they can leak badly according to the thousands of posts in forums.

**cabinetcrafts** · 9th Nov 2011, 20:07

Oh - there are 2 sunroofs on our disco and I see what you mean about the number of problems!! I assumed as the water was only obvious by the windscreen and the black trim round the windscreen looks dodgy that was the problem area. I'll have a look at the sunroof tomorrow when it's light.
No sirens on 'eBay' at the moment, will keep looking

**peterdon** · 11th Nov 2011, 10:01

If (or should I say when) your sunroof is leaking you will normally have water dripping from the interior light switch console above the windscreen. If it's not dripping from there it is filling with water.