Higgsy Posted August 14, 2015 Share Posted August 14, 2015 I am having issues with the alarm and central locking on my 2005 Defender. If you lock the truck with the key fob it beeps twice to tell you something is open. Nothing is open. If you do manage to lock it with the fob then within an hour or two the alarm will activate.If you try to lock it using the key in the door lock you hear and see the lock activate but it instantly unlocks. I have replaced all batteries in key fob and replaced the bonnet pressure/sensor switch under the bonnet. Does anyone have any ideas ? Cheers Alan. Quote Link to comment Share on other sites More sharing options...
Tanuki Posted August 14, 2015 Share Posted August 14, 2015 Check the plunger-switches in the door-pillars and tailgate that activate the interior lights. And the microswitches in the door-lock mechanisms themselves. A few other things worthy of note: If there's an insect [mine have been moths and grasshoppers] trapped inside the car they can trigger the ultrasonic "volume sensing" part of the alarm when they start leaping around. You can pull the wiring harness from the volume-sensor [top of B-pillar on drivers side] as a test. Equally, if the battery in the sounder [located behind the N/S headlamp] starts to die it can cause strange and inexplicable alarm behaviour. Quote Link to comment Share on other sites More sharing options...
Higgsy Posted August 14, 2015 Author Share Posted August 14, 2015 Check the plunger-switches in the door-pillars and tailgate that activate the interior lights. And the microswitches in the door-lock mechanisms themselves. A few other things worthy of note: If there's an insect [mine have been moths and grasshoppers] trapped inside the car they can trigger the ultrasonic "volume sensing" part of the alarm when they start leaping around. You can pull the wiring harness from the volume-sensor [top of B-pillar on drivers side] as a test. Equally, if the battery in the sounder [located behind the N/S headlamp] starts to die it can cause strange and inexplicable alarm behaviour. Thanks for that. Are the microswitches relatively easy to check and can the sounder battery be changed ? Quote Link to comment Share on other sites More sharing options...
Scotts90 Posted August 14, 2015 Share Posted August 14, 2015 Check the door buttons aren't sticking, mine weren't sliding down the plastic escutcheons very well and kept popping back up when locking...a bit of lube and they were fine. My taildoor switch was a bit temperamental, a good clean up to give it a good earth and it was fine. Quote Link to comment Share on other sites More sharing options...
Tanuki Posted August 14, 2015 Share Posted August 14, 2015 The 'plunger' light-switches in the door pillars are easy to check - they're each held in place with a single screw. Remove the screw, ease the switch out of the pillar, have a good look at it for any signs of corrosion. If it looks clean, apply a dob of white grease and refit. If it's corroded, don't bother trying to clean it - they're dirt-cheap even from the official LR dealer. The micro-switches on the locks - again, take off the internal door-cards, peel back the plastic sheet and have a look up inside: the switches are on the back of the door-latch mechanism. They tend to corrode - the inside environment of the doors can get up to 100% humidity if there's water in the bottoms of the doors and you park with the doors facing into the sun; this "sweats" the electrics in the door and corrodes everything. . . It's possible to replace the micro-switches with commercial-oof-the-shelf parts [from RS, Farnell or CPC] but it takes time and I'd rather just fit an entire new latch assembly [quicker, costs about the same overall if you're billing your time in 15-minute units to the client]. The BBUS battery's part of the sounder - normally its battery is recharged from the main vehicle-battery when the vehicle's in-use but after a few years the BBUS battery can get weakened and then it can cause problems: you get at it through the left-side headlamp hole [after removing headlamp]. See http://workshop-manuals.com/landrover/defendertd5/electrical/anti-theft_alarm_from_02my/page_748/ There's a process [involving disconnecting the main battery within 15 seconds of doing-things with the ignition-key] otherwise the BBUS will try to yelp. Quote Link to comment Share on other sites More sharing options...
studmuffin Posted August 14, 2015 Share Posted August 14, 2015 My alarm problems all started because my battery wasn't fully fit for the job. Worth checking. In the meantime welcome to the forum Cheers Barry Quote Link to comment Share on other sites More sharing options...
davie Posted August 15, 2015 Share Posted August 15, 2015 check interior lights too - i went through very same stuff which was cured by all new door switches and new interior lights, little corrosion in each but took me longer to figure out interior lights... this was in a 2003 td5 so i imagine its pretty similar, damp slowly worked in and upsets stuff. Quote Link to comment Share on other sites More sharing options...
Higgsy Posted August 15, 2015 Author Share Posted August 15, 2015 Thanks for all your help and thanks for the welcome to the forum ! Quote Link to comment Share on other sites More sharing options...
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