1992 400E Alarm Complication Question

[kowached]

My dad just purchased a 1992 400E with 50,000 miles and is having a problem with his alarm system. Sometimes (appearingly random) when he unlocks the car and opens the door the factory alarm goes off (just horn and flashing lights, no starter interrupt). Does anyone know a fix, or if there is a fuse or relay he can remove to permanently disable the factory alarm. I think I'm going to get him a remote start for his birthday anyhow and that would have an alarm as well to make up for the disabled factory one. Thanks!

[jc300e]

Had the same problem with my '87 300E. So far, my 400E hasn't presented the same issue.

My problem was the alarm sensor/relay/whatever you call it....on the driver's door lock had a fault. Every time i attempted to unlock the car from the driver's door the alarm would trigger. I was able to unlock the car from the passanger door and the trunk without the alarm sounding.

You can have the sensor in the driver's door replaced or you can pull it out and unplug it. Unless the '92 is vastly different, you will see a plastic cap on the inside of the door...about the same level as the door handle... If you pull the cap out, the alarm sensor will come with it and you will see the wiring harness. Unplug it and the alarm problem will go away...BUT..The alarm will no longer set from the driver's door..

Hope this helps...This, at least, was a quick fix on my '87 300E...Have fun !

[jsmith]

the lock cylinder is about $160 from the dealer. the contacts to disarm the alarm are probably worn out. some have said that it can be cleaned if the contacts are just dirty. another solution would be a keyless entry as described on this forum. do a search, it's about half the price of a new lock. BTW you can always still use the passenger side and the trunk to unlock/disarm the alarm system.

[kowached]

Thanks to both of you. I'll see if I can clean up the contacts on the lock, if that doesn't do the trick then I'll disable the alarm & get him the remote start with alarm a little sooner. Thanks again.

[bstreep]

A remote keyless entry should arm/disarm the factory alarm as well.