Door trigger & diode
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=9802
Printed Date: June 09, 2024 at 5:44 PM
Topic: Door trigger & diode
Posted By: sampoarE34
Subject: Door trigger & diode
Date Posted: February 20, 2003 at 1:40 PM
Hi,
I am installing a commando FM-760 alarm,
but the alarm has only 1 door (-) trigger input and my car 3 wires (driver,pass,rear doors) i want to use
diode to isolate the 3 wires from eachother.
But what ever diode i use the system will not trigger at all,i dont measure GROUND (-) at end of diode (mark facing the door-wire) when door is open en before the diode at door wire side i DO measure GROUND/NO-GROUND when doors are open/closed.
For some case the diode is never letting any signal trough i tried reverse direction/polarity of the diode without success.
Replies:
Posted By: Velocity Motors
Date Posted: February 20, 2003 at 1:56 PM
What year, make & model vehicle is this ?
-------------
Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA
Posted By: sampoarE34
Date Posted: February 20, 2003 at 3:20 PM
Its a BMW 520i from 1992.
Negative door locks,
i measure ground when door open en no-ground connection when doors closed all 3 wires (2 front,1 for both rear doors) but using diode the diode seems to block the circuit before the diode i still measure ground/no-ground but after the diode only no-ground so no connection when door opens or closed...
please help i tried different diodes 1N5408,1N4106,1N4104
Posted By: Velocity Motors
Date Posted: February 20, 2003 at 3:28 PM
I have some conflicting information but you will need to see what is right by testing: DOOR TRIGGER|br/gry,br/blu,br/ppl|- |anti-theft plug * Anti-theft plug or module located under rear seat on passenger side. Door wires also found at general module under rear seat on driver's side. Be careful handling this module, as rotating it can cause underseat grommets to suck out, allowing eventual water damage to the electrical system. Domelight supervision wire BROWN / red at anti-theft plug. All DoorTrigger YEL/BLU (-) DRIVER'S SIDE UNDER REAR SEAT BIG HARNESS ------------- Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA
Posted By: sampoarE34
Date Posted: February 20, 2003 at 3:45 PM
This is right : DOOR TRIGGER|br/gry,br/blu,br/ppl|
I used this wires thats not the problem.
the problem is the alarm box only got 1 door trigger input (-) so i want to isolate the 3 door trigger wires but when i use a diode the system doesnt trigger at all when armed & opening a door on purpose.
Because the diode seems to block flow from the - signal coming from door too the alarm box.
Reversing de diode doesnt solve problem.
I got the big-strip-mark facing the door-wire coming from door-contact-switch but no signal using DIODE.
without diode it works but i want to isolatie 3 door wires.
Posted By: Velocity Motors
Date Posted: February 20, 2003 at 3:57 PM
You have them like this diagram:?? 
------------- Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA
Posted By: sampoarE34
Date Posted: February 20, 2003 at 3:59 PM
Yes thats right,
but i dont measure any ground after the diode.
before the diode (on the door-trigger side) i DO measure ground when door is openend,
so with the diode in place the system is not triggered at all,seems to bee diode is blocking all current.
Could the - signal be to less Voltage (V) so it blocks flow to the alarm box?
Posted By: Velocity Motors
Date Posted: February 20, 2003 at 4:17 PM
You should be only using a 1N4001 1 amp diode. The ones you have may be too large ( 3 - 6 amp ).
-------------
Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA
Posted By: Phill McCrank
Date Posted: February 20, 2003 at 6:40 PM
try using relays. you need three relays. connect the door triggers to 86 (one to each relay) 12v to 85 ground to 87 30 to alarm brain ------------- Phill Bowen
Lead Installer,
Master of all trades.
Posted By: camino
Date Posted: February 25, 2003 at 8:20 PM
no need to use relay's,just install the diodes with the white strip facing the door pins,or the wire's ok?
diodes work like a bridge,only facing the white stripe to the most negative side.
Posted By: Phill McCrank
Date Posted: March 02, 2003 at 5:14 AM
read above camino he tried that already
-------------
Phill Bowen
Lead Installer,
Master of all trades.
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