Question about 1987 Mercedes-Benz 300-Class
Probably a dirty micro switch which is built into the driver's door lock. I believe you could verify this by using the key in the passenger front door or the trunk lock. Either of these, which are used much less, should unlock the doors without sounding an alarm.
Most people unplug the alarm module which is under the floor mats in the front passenger's area. If you want to try to clean the switch, a aersol can of tuner cleaner/lube from Radio Shack, will probably restore the function of the micro switch. Mercedes is notorious for using silvered contacts that tarnish just enough to hinder continuity.
Jim in Phoenix
Posted on Jan 24, 2009
a 6ya Mechanic can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repair professionals here in the US.
click here to Talk to a Mechanic (only for users in the US for now) and get all the help you need.
Posted on Jan 02, 2017
Tips for a great answer:
Jan 24, 2011 | 1987 Mercedes-Benz 300-Class
Jan 11, 2011 | 1987 Mercedes-Benz 300-Class
Sep 16, 2009 | 1987 Mercedes-Benz 300-Class
Apr 21, 2009 | 1987 Mercedes-Benz 300-Class
Apr 03, 2009 | 1987 Mercedes-Benz 300-Class
Dec 29, 2008 | 1987 Mercedes-Benz 300-Class
Nov 17, 2008 | 1987 Mercedes-Benz 300-Class
312 people viewed this question
Usually answered in minutes!
Step 2: Please assign your manual to a product: