Relay problems with door locks

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=59189
Printed Date: July 07, 2025 at 5:08 PM

Topic: Relay problems with door locks

Posted By: Spiderman68
Subject: Relay problems with door locks
Date Posted: July 10, 2005 at 9:50 PM

Hi all
Be nice i am new.....

I have fitted a RHINO RA alarm to my Ford (Mercury) Capri 1993 XR2... I am having big problems with the door locks...The doors have switches in each door console .the ,motors are both slaves and they both work of each button eg lock with one locks both..they work on a reverse power principle eg lock supplies pos and neg to the motor..unlock suplies the power opposite....

My problem is i use the -ve unlock/lock signal for the locking of the doors ....i have used the 4 relay setup that i found on this site......when i use an earth i select the doors lock and unlock but when i use the alarms trigger it is not powerful enough to latch the relays long enough to power the door locks.....help me please i do not want to put a central locking kit in and loose my switch control i want to keep it original

thanks

webby

Replies:

Posted By: hotwaterwizard
Date Posted: July 11, 2005 at 12:34 AM

Could this be the answer you seek?

Central Locking Interface
Some cheap car alarms do not have a connection for the central locking system.
However, in most it should be possible to find a point in the alarm circuit which
is high when the alarm is activated and low when it is off. This signal can then
be used to drive this relay circuit to operate the central locking system.

The interface circuit converts each toggle of the alarm signal to a brief pulse
to operate the two relays which then are then connected in parallel with appropriate
contacts on the master solenoid in the central locking system.

Frank Keller, via email.
https://www.siliconchip.com.au/cms/A_101580/article.html

posted_image

-------------
John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

Posted By: Spiderman68
Date Posted: July 11, 2005 at 3:32 AM

The alarm produces a lock and an unlock signal on seperate wires .....they are -ve pulses of 350ma

Webby

Posted By: Spiderman68
Date Posted: July 11, 2005 at 7:12 AM

Gday
i got it fixed.....i used the 5 Wire Alternating 12 Volts Positive Door Locks relay config from this site...had to wire it right near the drivers switch