Disabling Immobiliser on SA van

[marlinowner]

Hi, my immobiliser has gone wrong so that I cannot start the van, alarm goes off when doors are opened, etc. Put new batteries in remote, light on remote flashes but has no effect. Any advice on location of problem or how to disable immobiliser?

[Wychall]

I've had nightmares about this very scenario myself, ever since buying the vehicle.

Does your remote operate the central locking as well? Is that working? Are you able to turn the system off with the over-ride key? (What a lot of questions!)

The control box is behind the glovebox under the dash. As to immobilising the immobiliser..... you would need to get down and dirty with the wiring schematics to identify which wires are doing the actual immobilising. I've meant to do that very deed myself for a long time but haven't got round to it yet.

Shout up if you need any further assistance.

[marlinowner]

Bit tricky because I am out and about, now waiting for the AA...
Remote is doing nothing but central locking works with key. Don't have the over-ride key with me but can't get the system into the 30sec timeout which I think is a prerequisite for disabling the system?
Suspect AA relay will be required then an auto-electrics guy.

[Wychall]

Would the remote normally have operated the central locking? If it would, then the problem sounds to be the remote or its compatriot at the other end. Do you have a second remote at home to be able to check before paying out for the autosparks bloke? You do have a copy of the wiring diags to be able to show the sparky don't you?

[marlinowner]

I've got another remote once I get home which I will try. Think I downloaded the schematics but again can't check at the moment. I'm in Watford and home is Scottish Borders...

[Wychall]

From a quick peruse of the wiring diags, the immobiliser is simply a starter circuit cutout operated by a relay behind the dash. Try shorting the main starter solenoid terminal with the switching terminal. I believe that may work. Alternatively, the wiring from the immobiliser goes to terminal 50 on the ignition switch. Putt a live feed to that terminal should bypass the immobiliser.

Good luck.

[Wychall]

Ignore that last. The feed from terminal 50 on the switch goes through the immobiliser relay then on to the switching terminal of the starter motor. So, behind the glove box is a relay with the following wire colours.
Red/Black x 2
Black/Red x 3
The thicker of the Red/Black wires needs to be connected to one of the Black/Red wires (all thick) The immobiliser should then be cut out.

[marlinowner]

Well the AA arrived after nearly 2 hours but were redeemed when their man took out the glove box to reveal a veritable rats nest of wires bound up with masking tape. He then pulled a plug out of the immobiliser at which point everything started working except the central locking through the remote. Should get home later today when I will investigate further, but am quite happy as things are. Thanks for the advice, it was good to be able to tell the AA man that the immobiliser was behind the glove box. So the lesson to be learned is - immobiliser problem, just unplug it...

[MidLifeCrisis]

So the lesson to be learned is - immobiliser problem, just unplug it...

Glad you got it sorted but this probably shows that your 'immobiliser' isn't worth a whole lot if it can be defeated by reaching up inside the glovebox and yanking a plug out !!

[marlinowner]

That was my thought too! Although you do need a screwdriver to take the glovebox out on the SA vans!
It was factory/dealer fitted in SA so VW were happy with it...

[marlinowner]

Investigated this a bit yesterday evening, removed the glove box and had a look. Lots of strange looking wiring not connected to anything, bits rwrapped in masking tape etc. Anyway immobiser is mounted horizontally behind the glove box with two multi way plugs, the AA man had disconnected the inner one. Reconnected it and alarm went off but it all then worked correctly, remote central locking, immobiliser, etc. Still working today so glove box has been refitted, all I have to do is carry a screwdriver so I can disconnect it again if problem recurs. At some point I must tease out the mass of wires and try to make sense of it...

[marlinowner]

Well stopped for LPG at the same garage and it did it again... Must be radio interference there stopping the remote disabling of the alarm/immobiliser. Anyway now I know what to do I was going again in under a minute. Drove a few miles, reconnected it and everything working again. So if you have a SA immobiliser, I caution against stopping at the Shell garage opposite Asda in North Watford!

[Wychall]

Thanks for the warning. A very strange occurence though.