Central Locking + Alarm Hell [Archive] - VW T4 Forum - VW T5 Forum

Central Locking + Alarm Hell

03-12-08, 15:28
2 years ago I thought it would be a good idea to try and mess with the rear interior lights and basicly what ever I did, It didnt work so I got fed up and just put the roof board over it insulated it etc and built the rest of the van.

So the way my interior lights currently work is : I have just one in the cab and it switched off it will be off, but either the always on, or Door Open setting will always be on. So basicly my van always thinks a door is open probably something to do with my stupid messing around a few years back.

My central locking works perfectly and now when I connected it to the alarm today I ran into a few problems.

1) Alarm will start going off for no f'ing reason when in Alarm Mode.


2) Alarm Doesn't go Off.

However I think I have managed to get the fault down to one cable. it is Purple and in the manual it says it goes to Negative Triggering of Side Door.

There is also a Blue cable that i havn't used that is "Positive Triggering of side door" but I know the central locking works off Negetive Triggering as I think the interior lights do so I havn't used this cable.

Back to the purple cable, I noticed that my mate had connected this to the Earth of the Central Locking which I'm starting to doubt, as I think maybe it should have gone to one of the door triggers (the switch which the door will close when shut)

When I disconnect this purple cable from the equation the Alarm works fine but as there is only Vibration Alarm + Ultra Sonic I have tested that I can open any door sit inside get ed off its not working etc then leave the van eventually and the alarm doesn't even know I was in there.

SO I take it your Van's Inside Loom with the interior lights is important, What I am really asking is Do I have to take the whole roof down in the back and sort out the mess I made (I can deal with this) or is there a way round it, like wire in my own new (and not so old and stuck) door switches to that purple cable.

I would really like my alarm to go off when somebody tries to get in one of the doors!

Thanks for reading.

04-12-08, 10:49
??? anyone done a central locking before?

04-12-08, 15:38
sort the lights cause it could be the door switches causing your probs

04-12-08, 21:39
My factory fitted central locking gives a permanent live to the locks when locked and another permanent on unlock so connect the alarm to the live feed of the lock circuit to kill the alarm when you unlock.

If that makes sence:confused:


05-12-08, 12:10
not really sure what you mean there

Still having problems with this only cable

"Negative trigger"

Leaving this connected to nothing results in unlocking the van then it will lock it self in 25 seconds as it doesn't know ive got in there (it does if i move around a bit as the vibration sensor picks me up)

I have 2 master motors and one slave in the back, all have green and blue wires going to each of them (the front 2 have 3 more colors this must be for telling all the others to lock when down)

I've tried connecting to each of the green and blue, This way the van knows I'm getting in it at last when I unlock but when the alarm is set both ways it just goes off instantly.

05-12-08, 17:57
if its neg switch trigger for alarm it has to go to pin switches which earth out when doors open.

otherwise it will keep arming as it wont know youve opened the door....

06-12-08, 09:53
ok well i had no more opts left so the ceiling had to come down in the back to sort the interior lights. Anyone who has converted there van to a camper will know the deal that this was. BIG JOB> anyway my fault shouldn't have messed with it a few years back it came back and got me. Sorted out my wiring so the pins are all working. I do only have one interior light now which is in the cab but each door activates it.

There are 3 cables going to this light, one Is Red, and there is a white and brown and a brown. I am assuming Brown is constant earth and red is constant 12V (allowing the light to be on all the time when you want it to be) and maybe brown and white is the switched earth which must be connected too all the negative door switches somehow.

Touching this purple "negative trigger" too this wire in the light makes the system work perfectly when the alarm is on. As soon as any door opens the alarm goes off. HOWEVER unlocking my van and unactivating the alarm still has a problem. IT DOESN'T KNOW I HAVE GOT IN THE VAN OR OPENED A DOOR SOMEHOW. how is this possible. after 25 seconds it reactivates itself again.

On Earthing the purple cable the alarm knows I have got in and i don't get this problem however it then won't work with the interior lights syst.

this is ******.

06-12-08, 16:42
connect to brown/white

only time i get this i s when pin switches are dirty and dont drop down to earth( they stay at above 1volt then alarm doesnt see them as earth)

07-12-08, 17:12
ok will wire to brown/white, is this wire accessible behind the dash somewhere?

08-12-08, 13:31
still nightmare, 4 weeks of wires everywhere I think I am really at my last resorts here or its coming out. On the plus side the central locking can stay in but will have no key fob.

a mate said today just earth out the "negative trigger wire". in doing that the alarm just goes off all the time. He says he did the exact same thing and his alarm senses a voltage drop (when the lights go on) and it goes off.

Connecting to white/brown works perfect somehow the alarm knows when som1 is trying to get in there (when alarmed) but when I turn alarm off It never knows I have got into the van. (even on shaking vibration sensor opening doors loads and touching ultra sonic)

08-12-08, 13:32
therfor re alarming it self after 25 seconds.