retained accessory power

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=102184
Printed Date: May 12, 2025 at 6:29 PM

Topic: retained accessory power

Posted By: joshh
Subject: retained accessory power
Date Posted: February 13, 2008 at 11:18 PM

I have a viper 5002 system that I am going to install in my car over the weekend. I wanted to retain accessory power in my car after the key is taken out until a door is opened.

The alarm has a retained accessory output that shous ground until the door is open/closed or the system is armed. I knew that I had to use a relay for this but was not sure if I was doing it correctly.

85 : 12V+
86 : Retained Accessory output on alarm (-)
30 : 12V+
87 : Accessory Wire

What is powered off of the accessory wire? What I also could do is connect 87 to the 12V+ wire of just the radio (for radio functionality only). Though, I think I would have to use a diode for this to work. I believe the cathode side of the diode would be on the radio side of the wire (12V+) going from accessory to radio. Is this correct?

Replies:

Posted By: Twelvoltz
Date Posted: February 14, 2008 at 6:54 AM

What is the make/model/year of the vehicle?

If you do not know the current draw of the radio itself it will be difficult to say what size diode you would need. My suggestion would be to wire it up to the accessory wire in the ignition harness that powers that circuit. The diagram you posted looks to be correct, you would need to fuse the supply wire to the relay.

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Installer, IT support, and FFL. I need less hobbies.

Posted By: joshh
Date Posted: February 14, 2008 at 4:35 PM

I have a Nissan Versa S 2007. But, I've installed a pioneer headunit (DEH-P6900ub) into the car.

I am going to fuse the 12V+ wire. Will probably take the power from the wire that I am going to be running to the alarm.