# need relay help



## kfr291 (Aug 11, 2012)

hey guys, so if anyone has been following my buld thread ( a bit not updated right now ) i have been working on a LED bow tie. the one i bought kept breaking so i made one myself from scratch. 

SO THE ISSUE i have blue LEDs and red LEDs. the blue will be runners while the red will be brake lights.... i need a relay that will turn off the blue lights when the red ones come on. i was thinking of the relay that is used for fog lights.... we cant have fogs on at the same time as highbeams.... simular idea that i am going for. if anyone could help that would be wonderful


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## NYCruizer (Jul 10, 2013)

not following you. Are you thinking to have the rear bowtie blue while you're not braking and red when you are braking? If so - you'll want to be very conservative with the blue (otherwise you'll be a cop magnet) (bright blue or red on the front would achieve the same magnetic effect.


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## Mick (Dec 31, 2011)

Nycruiser is right, if a cop is behind you and sees the blue and red flashing you're bound to get pulled over. I recommend you stick to a solid color.

Sent from AutoGuide.com Free App


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## brian v (Dec 25, 2011)

Would red and green create the same or similar magnetism ?
Or even blue and green , yellow and orange . color choices brother ..


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## NYCruizer (Jul 10, 2013)

NY - Blue is volunteer fire, Blue in combination with red is an additional issue as "blue dots" were outlawed back in the 60's. Green is volunteer medical response (EMT), Red is restricted to emergency vehicles (Fire/Police). Orange/Yellow is essentially service vehicles. Decorative lighting on the outside of the car is like putting a "free donuts" bumper sticker on your car.


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## sciphi (Aug 26, 2011)

So, you want the glow-tie to be blue with normal driving, and then turn red when the brake lights come on. 

You need a SPDT relay. Power source for glow-tie would go to terminal 30, glow-tie blue LED power would come from terminal 87A (normally closed), red LED power would come from terminal 87 (normally open), and brake wire would be tapped and lead to terminal 85. Terminal 86 is your ground, plus wherever you ground the glow-tie to. 

I hope the blue LED's are very faint, or cops will be all over your car.


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## Xaxas (Jun 1, 2013)

Using Relays To Wiring Off Road Lights And Accessories

This really helped me out, until now I never really understood how relays worked, as far as I can tell, you will need a relay
Amazon.com : Absolute RLS125 12-VCD Automotive Relay SPDT 30/40A : Vehicle Electronics Relays : Electronics
And the other stuff people buy together with it (the socket and the fuse holder)

And it would go something like:

30: Fused Battery
85: Ground
86: Brake Light
87: Red (Brake) LED
87a: Blue LED

This way, when you press the brake, there is current going through pin 86 (brake light), the magnet coil is activated, lowering the gate to the pin 87 and thus, activating the red LED, otherwise, the gate is connecting with the 87a pin, meaning that when there is no current in pin 86, you will always get 12v into pin 87a, which are your runners lights.

http://www.sigcorps.com/v/vspfiles/assets/images/5%20pin%20power%20replay%20diagram.jpg

Note, this is just what I learned from relays, and I can't guarantee this will work, but as far as I've learned, this is how a 5 pin relay works.


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## kfr291 (Aug 11, 2012)

yeah sorry guysm been majorly busy so wrote this qucikly... i am not talking about it flashing between the two colors like PD does... i am saying when the running lights are on it will be blue and when i hit the brakes it will turn to just red.... i am in no way making it flash or strobe between two, but thank you for the heads up... trying not to attract the police

i do have blue LED on now... its just the rear bow tie outline... you can only see it on the trunk.... the blue LED come from a automotive store meant for out of car use. i am runnign them i have photos of the oringal bow tie on here let me see if i can locate it ( the lat photo is the finish product ) http://www.cruzetalk.com/forum/57-how-library/12172-how-install-led-bow-tie.html 

i did a remake of it, to improve the reliability 

lastly


THAKN YOU ALL SO MUCH this helped alot. i knew i needed a relay ( 3 failed relays ) just did not know which one would be the best fit. thanks again guys. i hope this trhead helps others


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## kfr291 (Aug 11, 2012)

how do you know what relay to use as a general idea?


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## sciphi (Aug 26, 2011)

kfr291 said:


> how do you know what relay to use as a general idea?


My bad for the late reply. Basically, it boils down to what you want the relay to do. If you have one thing that is off right now and needs power when told to turn on, a single-throw relay is needed. If you are changing what is receiving power already, a double-throw relay is needed. That is my understanding, at least. I'm no expert at relays by any means. My headlight harness taught me quite a bit about wiring simple circuits, though.


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## kfr291 (Aug 11, 2012)

o yeha no issue on the lateness. currently i do not check here untill early morning... my work has me working from early afternoon to early morning.. cool seems simpleenough, and then once you figure out how many throws its just a matter of making sure that it can handle the power.


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