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2 different 12v circuits to 1 led light?

Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=136596
Printed Date: May 02, 2024 at 12:47 PM


Topic: 2 different 12v circuits to 1 led light?

Posted By: beachbum561fla
Subject: 2 different 12v circuits to 1 led light?
Date Posted: May 07, 2014 at 1:08 AM

i have external LED lights that i installed in my bumper today. they are 2 way (3 wires: 1 ground BLACK, 1 positive WHITE to parking lights, 1 positive YELLOW to either Turn Signal or Brakelights).

right now i have them hooked to my turn signals.

i'm wondering if there is any way to be able to hook that yellow wire to my brakelights as well by using some relay(s) and i would assume some diode(s) so nothing back feeds to the actual brakelights on the car.

any help would greatly be appreciated.



Replies:

Posted By: beachbum561fla
Date Posted: May 07, 2014 at 1:27 AM
would just this work?
posted_image

or this diagram?
EDIT: Image removed at request of image/site owner.




Posted By: howie ll
Date Posted: May 07, 2014 at 9:03 AM
Probably but having front ambers come on with your brake lights poses lots of legal problems.

-------------
Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.




Posted By: beachbum561fla
Date Posted: May 07, 2014 at 11:10 AM
all this wiring is done in the back of the car. not the front. your laws in UK may be different than USA. we're allowed to have amber up front but i'm pretty sure the trailer converter i posted will work. but if there is another way i'd like to know that as well for future reference




Posted By: howie ll
Date Posted: May 07, 2014 at 11:23 AM
We got mixed up!
I like a fool assumed you meant front bumper.
You can do it via 3 amp diodes, split your indicator feed via a pair of 1N5404 diodes each side.

-------------
Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.




Posted By: beachbum561fla
Date Posted: May 08, 2014 at 8:16 AM
howie ll wrote:

We got mixed up!
I like a fool assumed you meant front bumper.
You can do it via 3 amp diodes, split your indicator feed via a pair of 1N5404 diodes each side.


2 diodes per side? or just 1 per side for a total of 2 for 2 turn signals (left & right) ?




Posted By: howie ll
Date Posted: May 08, 2014 at 8:57 AM
2 per side, prevents feedback.
3 diodes per side, I just roughed this up for you:-

led.bmp

-------------
Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.




Posted By: beachbum561fla
Date Posted: May 08, 2014 at 10:43 AM
howie ll wrote:

2 per side, prevents feedback.
3 diodes per side, I just roughed this up for you:-

led.bmp


i tried that and it didn't work. i think i may have you confused so i made a mock up of the wiring i have.

if you can tell me where to put diodes that would help.

i am only using the brakelight input on the passenger side because the taillight converter itself only has one input wire.

when i hooked up the taillight converter first try with no diodes, everything worked except the issues were:

brakelight flashing with turn signals rapidly
brakelight flashing with hazard lights but at slow speed

when i put on the diodes like you have, it killed the turn signals completely on the LEDs as well as the brakelights.

posted_image




Posted By: beachbum561fla
Date Posted: May 08, 2014 at 10:45 AM
also, i don't need that ground output since the application i am using is already grounded. that ground wire is only for an actual trailer wiring harness that has no ground on the trailer. that wire is taped off.

i'm also not using the running light wires since the led modules have an additional wire that is already hooked to the factory parking light wire and the parking lights plus the led modules light up fine with no issues.




Posted By: beachbum561fla
Date Posted: May 09, 2014 at 8:00 AM
nevermind. i got it and ended up not needing any diodes. it turns out i guess my car has some type of safety brake/flasher. if 1 of my actual taillights are unplugged, then it makes the 3rd brakelight into a hazard light, hence why that light kept flashing.

so i plugged in both lights while still testing the unit and made sure connections were taped temporarily and everything works fine.

the only thing i notice (which doesn't bother me at all), is if i am on the brake and using either turn signal, the turn signal (OEM) and the LED lighting up aren't synced with each other but when i let off the brake they are. no big deal!




Posted By: howie ll
Date Posted: May 10, 2014 at 2:50 AM
Don't worry,LEDs and filaments need special circuitry to work in synch.

-------------
Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.





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