Alarm - auto arming

[CRJ343]

I have an E220 Cabriolet fiited with the standard MB alarm/immobiliser system.
Is there any way I can stop the alarm/immobiliser from autoarming when I switch off the engine e.g. when waiting in a traffic queue ?
To disarrm I need to get out of the car and aim the keyfob at the door handle

[grober]

I don't know exactly how your alarm is wired but I assume that in addition to a constant 12v supply from the fuse box there will also be a ignition switch sensing circuit which gets a 12v when the ignition is switched on. If you were to rewire this to a unswitched constant 12v supply this would probably disable the auto arming. You would however have to check that you can still arm the alarm system manually. If you couldnt you would have to put a hidden manual switch in the this "defeat" 12v line to power it down. This is beginning to compromise the alarm system so think carefully .

[recycled]

Are you saying it arms itself while you are sat in the car?when you switch off?
Is it not when you lock the door that it does this?

[CRJ343]

No if you turn the engine off after about a minute the lights flash and you need to disarm the immobiliser. On my model you can't lock the doors with a "key" , only with the fob. Unlike the R129 (SL) there isn't a sensor in the main mirror only in the driver's door and boot handles so you have to get out of the car to effect the disarming.

[del320]

I presume you have a red/green LED in the drivers' door handle instead of a lock?

If so, you can not switch off the immobilisor unless you go down the route suggested by grober. These systems were fitted by MB dealers and are cr@p. The biggest problem is that if your key fob battery fails and you don't have another at hand, then you are stuffed. Always carry a spare working fob and/or batteries.

If, as happened to me, the LED fails, you are completely stuffed! The circuit can be bypassed but as this is an open forum, you should consult a friendly auto sparks or your MB dealer to show you how. It is a simple operation when you know how, but when you are in the middle of France on a Sunday, watching your Merc being winched onto a low loader, you have a humour bypass!

Meantime, live with it. If you're waiting outside the newsagents whilst O.H. dashes in for some sweeties, turn off the engine then immediately turn key to position 2.

[recycled]

Sorry what year is this car.
I think there is a plug where the red key fits into in the glove compartment or by the drivers leg in the footwell to disarm the car .

[CRJ343]

Sorry what year is this car.
I think there is a plug where the red key fits into in the glove compartment or by the drivers leg in the footwell to disarm the car .

Thanks but this is 1996 model with airbags so there is no (front) glove compartment.
The only alarm key I have is (I assume) for the siren and that is located in the engine compartment.

[grober]

Take a look at this thread also. http://mbclub.co.uk/forums/showthread.php?t=30876&highlight=scorpion
you need to be logged on to this forum to see it.