Door locking on Mercedes

Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=7716
Printed Date: May 10, 2025 at 2:32 PM

Topic: Door locking on Mercedes

Posted By: fishmonks
Subject: Door locking on Mercedes
Date Posted: January 06, 2003 at 4:02 AM

Greetings all,

I have just registered and have searched through the archives for help, but was unable to find what I specifically need.

I have a Mercedes vehicle and wish to install a lock/unlock switch to lock/unlock the central locking, which is the vacuum pump driven type.

Currently when doors are locked, a single wire to the pump from the drivers door is at ground. When unlocked, the same wire becomes +12V.

The switch I am using has 3 pins on the back, and is a rocker type momentary contact switch. When pressed up it should lock the doors and when pressed down it should unlock the doors.

(I have seen the relay wiring diagram under the 'Door locks' section, but that works with a 2-second pulse)

I would really appreciate if anyone could help me here - I've almost fried my brain trying to figure it out using SPDT relays. I have figured out a way using my alarm unit, which locks the doors on start-up, but I wish this switch to be independant, so I can sit in the car and lock/unlock the doors from this switch anytime I wish.

I'm guessing I will need to wire up at least 4 SPDT relays in a certain sequence, but I am struggling to figure it out.

Many thanks in advance,

Fishmonks

Replies:

Posted By: brianh
Date Posted: January 06, 2003 at 6:13 AM

What year?What model? Brian

Posted By: fishmonks
Date Posted: January 06, 2003 at 6:14 AM

Hi Brian,

The vehicle is a 1986 Mercedes 560SEC.

thanks

fishmonks

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fishmonks

Posted By: auex
Date Posted: January 08, 2003 at 5:14 PM

I think you could wire a dei timed pulse module. If I remeber right it should see a pusle and you can extend it with this module for however long you need. Or you could just hold the switch for a couple of seconds.

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Posted By: the12volt
Date Posted: January 08, 2003 at 5:21 PM

The easiest solution would be to use your rocker switch with the two relays shown here unless you absolutley do not want to hold the switch in either direction for up to two seconds. Let us know.