1999 SL Motion Sensor Deactivation

[niva441]

Hello all

I recently bought a SL320 that I was asking for pre-purchase advice in an earlier thread. All is going well and I'm mostly delighted with the car, with just a couple of minor issues needing sorting.

One question the specialist wasn't able to answer was how to deactivate the motion sensors, for when the dog is left in the car. The car is fitted with the standard period Mercedes alarm. According to the supplied manual there is a LED/switch on the drivers door pillar that when pushed disables the motion sensors. I have found the LED/switch, however it doesn't seem to push in, but flips left/right. Neither position affects the motion sensor operation.

Has anyone got any clues how I deactivate the sensors, also what is the purpose of the LED/switch on the door pillar.

Thanks

Todd

[r129sl]

For some unknown reason, the security system fitted to the 1999 R129 is not factory. Rather it was installed in the UK and is a Cobra system rebranded MBSS1 or 2. You should have some instructions for it with the car. One of its unfortunate feature is what appears to be a red LED which has to be positioned somewhere in the car. Different dealers put this in more or less obtrusive places. Mine is on the lower dash under the instrument binnacle. If I remember correctly (I do not have my handbook to hand), in order to deactivate the interior motion sensor, you must press in this LED before getting out of the car. I have found it makes no difference at all.

[niva441]

Not being factory fitted does make sense with some of the statements in the manual (and it's style). If the door LED/switch is a red herring (although what else could it be?). This switch didn't push in, unless it's already been pushed too far.

I'll have another look and see where else the switch might be, although having replaced the radio, I've had a reasonable look through the interior.

Otherwise I'll be putting either grommits or tape over the motion sensors.

Thanks for the information, I'm particularly interested that your switch doesn't seem to have any effect.

[bolide]

If the car has a dealer-fit alarm with a Mercedes-branded key fob remote (not a flip-out key) then there should be a slide switch on the side of the remote. In one position the interior sensors are on - and, in the other, they're not

If you have RCL central locking with the infra-red flip-out key then it'll be via the pushbutton

the simplest solution all round is to rip out the old alarm & replace it

Nick Froome
www.w124.co.uk