W168 (A140) Alarm problem

[Vectrolosys]

Hi there,

A colleague of mine has a 1999 W168 A140 that has an annoying problem. The remote central locking has recently stopped working (replacing the fob battery has not resolved the issue) so the car has to be unlocked via the door lock. However, this sets the alarm off, which continues to sound even when the car is driven and lasts for about 15 minutes before stopping.

I was wondering where the alarm sounder lives and if this can be safely disconnected to silence it, whilst the root cause is investigated.

I know on other cars (such as Vauxhalls) if the internal battery in the sounder starts to go, this can cause the problems being experienced here with the alarm sounding at in-appropriate moments.

I was wondering if anyone was able to cast light on the issue and also the remote locking problem as it's likely the two are related.

Thanks in advance,

James

 

[rubbergrape]

Hi James,

a bit of a late reply but for the benefit of others ...

From memory, disconnecting the alarm will just set it off. It has an internal battery. disconnecting it will make it think its being attacked and it will scream at you.

About the remote unlocking problem. I seem to remember when I got a new spare key from merc, there was a paring process to go through before the the remote fob would work.

Basically it is to teach the car to recognise the key fob. maybe the car has "forgotten" maybe it needs re-teaching?

I can't remember the process - it was something like pressing the unlock button 3 times with the the ignition on whilst pressing the clutch and standing on your head. Have a search on line or ask MB Bristol.

BTW MB insisted on seeing my ID and registration documents before they would get me a new key for obvious reasons - so remember to take that stuff along to merc with problems like this.

 

[m7m]

Not sure of the A140, but as far as I know the siren in under the front right wing. I have seen a Merc with the alarm siren's wires disconnected. When the alarm is on, the hazard lights flash quitely.