Strange thing on my Keyring?????

[Sullivj]

Hi guys,

On my W140, I have a small black plug 'thingy' on my keyring. I've realised that it plugs into a slot, next to the alarm LED, just under the handbrake handle. I guess it's something to do with the alarm but I don't know what?! I also have a red one of these 'thingys'!

I've not been brave enough to plug it in. Can anyone tell me what it's for?

Thanks,
John

 

[pascal]

Keep the red one safe at home.

You can put the black one on your keyring for emercencies. If you find your remote does not work, open door with key, (alarm will activate) and insert key in slot and remove.

If you ever loose the black key, the red one can be used to program a new black key.

 

[Sullivj]

Thanks Pascal. Once again, you prove to be the fountain of Merc knowledge!

Thanks again.
John

 

[peterchurch]

Its worth having a dry run with it by taking the batteries out of your keys and trying the plug for real before you need it on a cold wet day when your sense of humour is frayed

 

[pascal]

You don't have to do that to test it.

Just open the the door with it's key (first remove plastic key cover), and alarm will go off. Insert alarm key in socket. Should disarm.

Note: Alarm, door/boot/bonnet and motion sensor takes 40secs to arm after setting. Alarm associated with ignition switch arms immediatly.

PS: This applies to Thacham Cat 1 alarms fitted for the UK market. (MBSS 2b etc)