neg pulse

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=105292
Printed Date: May 15, 2025 at 5:46 AM

Topic: neg pulse

Posted By: shepbears
Subject: neg pulse
Date Posted: June 06, 2008 at 2:00 PM

Hi, I'm looking for a way to get a negative pulse when I hit my lock button, but only when the car is off. Thanks

Replies:

Posted By: shepbears
Date Posted: June 06, 2008 at 2:19 PM

sorry i dont know how to edit my post, but i have 2 relays wired so far but it sends a signal when i turn my car off and i need it ot just send when i hit the lock

Relay 1
86 - ignition
85 - ground
87a - 87a of relay 2
30 - ground
Relay 2
86 - (+) lock motor wire in drivers door
85 - ground
87a - 87a of relay 1
30 - to (-) trigger input of window module

Posted By: dualsport
Date Posted: June 06, 2008 at 8:18 PM

You could just wire one relay like this:
posted_image

If your ignition is turned off, and you work the door locks, the relay should pulse and send your neg pulse.
If the ignition is on, the relay won't do anything if you hit the door locks.

One note on this: the switched 12V line you tap into has to be one of the higher draw lines, like the actual ignition, because this relies on it acting as a virtual ground for the relay. If it's a switched source that doesn't draw much power, it might not draw enough current to energize the relay.

Posted By: shepbears
Date Posted: June 07, 2008 at 5:34 PM

Thanks a lot it works fine now.