How to get 12volts when key is off only?

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Forum Name: General Discussion
Forum Discription: General Mobile Electronics Questions and Answers
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=38106
Printed Date: May 03, 2025 at 10:05 PM

Topic: How to get 12volts when key is off only?

Posted By: Bearington
Subject: How to get 12volts when key is off only?
Date Posted: August 25, 2004 at 9:11 PM

No alarm system. I need to power up my snazy LED but I dont want it to flash when I'm driving.

Replies:

Posted By: Bearington
Date Posted: August 25, 2004 at 9:15 PM

Oops wrong forum, sorry

Posted By: backinblack_gp
Date Posted: September 07, 2004 at 8:40 PM

Use the normally closed contacts of a double-throw relay to supply power to your LED. Drive the relay coil with the accessory circuit.

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Posted By: shldofbenacwboy
Date Posted: September 07, 2004 at 8:51 PM

run 12volt constant to your led's constant lead, and attach the ground side of the led to your car's true ignition which will read ground untill you turn on the key in most vehicles, thus turning the led off when the igition key switch is on. be sure to fuse as needed.

Posted By: backinblack_gp
Date Posted: September 14, 2004 at 8:38 PM

*MOST* automotive ignition (+) feeds will only go open when not active. They will not go to ground when inactive. Open circuits do not light LEDs...

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Posted By: Ravendarat
Date Posted: September 14, 2004 at 11:21 PM

Hooking the ground up to the main ignition wire in the main harness will work 99.9 percent of the time. Quick and easy, no problems

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Posted By: Bearington
Date Posted: September 15, 2004 at 6:44 AM

Great. Thanks for the replies guys

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