2 alarms on domelight circut

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=4894
Printed Date: May 15, 2025 at 2:41 PM

Topic: 2 alarms on domelight circut

Posted By: caferaceman
Subject: 2 alarms on domelight circut
Date Posted: October 28, 2002 at 2:38 AM

I am instaling an alarm in an S10 and am going to use the dome light circut to trigger my alarm for the door pins. No big deal. Well I also have a pioneer deck with a DFS Alarm on it and would like to hook that up to at the same time. My question is that when the doors open and current is put through that wire to activate the dome light and regular alarm, would it be to much draw for that circut to activate both the regular alarm and the DFS alarm. Would I have to put a relay at the top of the circut then to the domelight, alarm, and DFS? I guess it's kind if over kill but I'm in an alarm kind of mood. Each alarm will also get 2 sirens, one inside and one outside, using relays of course. Any help is appreciated. Thanks to everyone on this site for sharing their information and experiences. It's been a big help! posted_image

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caferaceman

Replies:

Posted By: Velocity Motors
Date Posted: October 28, 2002 at 5:12 AM

The trigger will be enough to trigger both alarm systems. You will not need to use a relay to boost the signal.

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Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA

Posted By: caferaceman
Date Posted: October 28, 2002 at 9:27 AM

Velocity, thanks for replying so fast. I've got another one for you...

At the relay between the alarm brain and the two sirens running of off the alarm, where should I get the constant 12v from for the relay and what size fuse? I can go from under the dash where I have power going to the alarm or off of the battery. My concern is that my alarm has a 9v backup battey inside the brain to run the siren if someone gets underneith and cuts power. If they do cut power I want to make sure the relay running the two sirens is still going to get power so my sirens will work or my back up battery would be useless. I guess I would not have this problem if I stuck with one siren, then I wouldn't need a relay that needs power.

Also, on the whole DFS Alarm thing. Would it be OK to tap in to the wire harness adapter going between my factory stereo plug and my Pioneer deck using the constant 12V /W fuse (what size fuse?) and ground for my relay to run two sirens off of it? I am going to use a 30A relay like I'm supposed to but whats weird is that in the Pioneer manual they say to use a 30A fuse going to the relay that's why I asked you above what size fuse to use. 2 sirens cant draw more that 5A's max, if that. Right?

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caferaceman