Wiring multiple sensors to 1 (-) input

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=37679
Printed Date: September 05, 2025 at 7:34 PM

Topic: Wiring multiple sensors to 1 (-) input

Posted By: ryan2000
Subject: Wiring multiple sensors to 1 (-) input
Date Posted: August 18, 2004 at 3:56 PM

I am about to install 3 sensors onto my stock alarm which has 1 accessory sensor input, which is (-). These sensors are DEI 504M (shock) DEI 508D? (proximity) and a mercury tilt sensor for the hood which uses no electronics, just a open\close circuit. Correct me if I'm wrong but will putting in a 1N4004 diode on each of the alarm-to-sensor trigger connections prevent any faulting from the other sensors? Thanks in advance

Ryan

Replies:

Posted By: auex
Date Posted: August 18, 2004 at 4:53 PM

There shouldn't be any problems not using diodes if you are not tieing into any factory switches, I would still recommend using diodes anyways. If you are using a factory switch then diode isolate all inputs.

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Posted By: ryan2000
Date Posted: August 18, 2004 at 5:19 PM

What makes a factory switch different then an aftermarket switch? I am going to be using 1 input lead (my stock alarm has an optional hood switch input, which I dont have installed so I'm using that lead) for 3 different sensors. If one of the sensors triggered wouldnt that current travel up the (-) lead of the 2 other sensors and cause problems?

Posted By: auex
Date Posted: August 18, 2004 at 6:05 PM

Factory switch ties into the car's electrical system. Say you have a glass sensor and an oem hood pin, every time your glass break sensor goes off it also tells the car that the hood is open.

-------------
Certified Security Specialist
Always check info with a digital multimeter.
I promise to be good.
Tell Darwin I sent you.

I've been sick lately, sorry I won't be on much.

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