Mercedes & aftermarket keyless entry

Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=39785
Printed Date: August 13, 2025 at 12:08 AM

Topic: Mercedes & aftermarket keyless entry

Posted By: HTFAN1
Subject: Mercedes & aftermarket keyless entry
Date Posted: September 26, 2004 at 5:16 PM

I researching installing an aftermarket alarm (Clifford) on a 1995 Mercedes C-Class. However, there seems to be a slight conflict in the documentation available on this.

The general vacuum lock information mentions a single "central vacuum lock" wire that changes polarity depending on lock status. There is a diagram documenting how to cut this wire and incorporate 2 relays to make the keyless entry fuction. (I can't find this wire.)

However, the wiring info on this site and others mentions two wires (I've found these wires.):

Power Lock:
BLACK (-)
DRIVER'S KICK PANEL

Power Unlock:
BLUE (-)
DRIVER'S KICK PANEL OR TRUNK

NOTE: I did some testing. Both wires rest at 12 volts and go to 0 volts when driver side key turned for lock or unlock.

What wires and diagram do I use?

Thanks,

Jeff

Replies:

Posted By: mo12v
Date Posted: September 26, 2004 at 5:23 PM

I have:

Power Lock	BLACK	DRIVER KICK
Power Unlock	BLUE	PANEL **

* Split Parking Light System - Must Use Two S.P.D.T. Relays Or Two 6 Amp Diodes To Isolate. **Negative Pulse Door Lock

-------------
MO

Don't Learn from Others Mistakes
You Might Be the One That Knows.

Posted By: HTFAN1
Date Posted: September 26, 2004 at 5:30 PM

This is new information. Thank you MO!

So, am I to assume that I use the two relays to isolate a 3.5 sec pulse to ground for each wire (depending on lock or unlock)?

Am I close?

Posted By: mo12v
Date Posted: September 26, 2004 at 5:33 PM

U can use the LOCK /UNLOCK wires from your unit (if they have Negative pulse) or the relays (for a better Ground)

-------------
MO

Don't Learn from Others Mistakes
You Might Be the One That Knows.

Posted By: HTFAN1
Date Posted: September 26, 2004 at 6:19 PM

Thank you again MO!

Where did you get this information? Is there a site I can reference too?

It looks like this is considered a "Type B - negative pulse" system in the Clifford manual.

Is this correct as far as you know?