led lights remain on
Printed From: the12volt.com
Forum Name: Lights, Neon, LEDs, HIDs
Forum Discription: Under Car Lighting, Strobe Lights, Fog Lights, Headlights, HIDs, DRL, Tail Lights, Brake Lights, Dashboard Lights, WigWag, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=133018
Printed Date: May 10, 2025 at 11:00 AM
Topic: led lights remain on
Posted By: britelightleds
Subject: led lights remain on
Date Posted: December 18, 2012 at 3:46 PM
installed into a car,a 12V LED Light stays on,
what is the correct way to calculate the correct resistor to use to put load into the circuit?
is there any other ways can put out the light that stays on very dim?
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Thank you for reading
Rhys
Replies:
Posted By: oldspark
Date Posted: December 18, 2012 at 5:02 PM
A resistor won't do it, it's probably a circuit that still outputs a voltage or current. One or a few series diodes may do the trick.
Posted By: soundnsecurity
Date Posted: December 28, 2012 at 11:19 AM
i have noticed the same issue with my dome and map lights staying on very dim when they arent actually on, i did some tests and i cant really figure out why because the circuit shows no voltage unless the switch is on. i think the only way i can make it act right is to completely rewire the lights and relay isolate the lights from the car. honestly to me its not worth the work to fix this issue but if you want to try out my solution then ill tell you how to test and rewire the lights.
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Posted By: KPierson
Date Posted: December 28, 2012 at 2:08 PM
Many solid state outputs have a certain amount of leakage current. This leakage current is not noticeable with incandescent light bulbs because they require substantial current to operate. However, with LEDs a milliamp or less can be enough to be visible.
The trick is not to put resistance in series with the LED, but in parallel instead so you are applying a direct load to the leaking output transistor. I would start with a 4700 ohm resistor and go from there. Hopefully that will be enough current (2ma) to force the LED off.
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Kevin Pierson
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