so i resently put on a shaved CF trunk and have no 3rd brake light.
i went to a junk yard and got a housing that fits in the rear window of the car.
well i got an LED strip from Oznium.com and wired it up

when the car is on, the LED strip is lit up very dim like its a running light, but i know for a fact its wired to the 3rd brake light wires only.
then when i hit the brakes it lights up to it full intinsity.
when i turn the car off... the LED strip stays on very dim like when the car is running, it stays on for like 5 minutes then goes out

help me! do i need a resistor so it is either competely off or at its full brightness?

 

you need a diode. try buying a 1a diode and touching it to the pos and neg wire. it should sove your issue but im not 100% sure

 

can i get one at radioshack?
i know they have resistors and diods and stuffff.....
i took a class for all that **** but i dont remember much of it.

anyone know anything else?

 

ya they should have a few different ones

 

do you think they would know how to fix it if that doesnt?

 

probably not... sometimes you'll get someone thats smart and knows what they are doing but most dont

 

haha thats true. kinda like autozone. bunch of dumbasses that think they know cars.

alright, a goodnight bump lol

 

i bet your cruise control doesnt work either. mine didnt. i bought a load equaliser from autozone and wired it in.

 

wait why would it not work?

 

something about it needing to see resistance. i have the nighthawk 3rd brake sold my mod preformance for a while and ive never had issues. but im pretty sure the diode thing will fix the low light issue

 

i actually called a few places and did some research and i need a relay switch.
from what i hear that will fix it.

 

why would a relay fix it? trust me try the diode. same thing happens with my dome light. its due to the LED drawing so little current

 

he's right. a relay uses small voltages to switch on and off big voltages. a diode corrects current flow. So basically what's happening is the LEDs are not drawing enough power and as a result, is sending electrons back through the positive wire. a diode will correct this.

 

A diode will correct the feedback keeping it lit at all times, but if your cruise doesnt work youre going to need to wire in a resistor( or an incandescent bulb) into the circuit)

 

Yeah problem is that there is some "residual" current in the wiring because the incandescent bulbs take a fair bit more current to light up... you'll see the same thing if you swap to an LED dome light. Wiring up a resistor in parallel should solve it.

 

i got it all working a while ago so its all good. cruze works too.

the relay worked so idc

 

mind if i ask how u hooked up said relay?

 

there were numbers on the relay for each wire, but its in the car now so idk those. all i know is one went to the LED, one i spliced from the positive on the 3rd brake light wire, one went to the battery, and one went to a ground. and evething works fine.
there were 5 wires. i used 4. the 4th in the middle of the relay is for it to be used with other relays so i just cut that one.

 

Emp....you would hook up the relay like it was the load in the circuit. give the control side of the relay a ground on pin 85 and feed the 3rd brake lamp power into pin 86, then attach your LED to pin 87, and the brake power feed to pin 30 as well. The relay he's using is probably a big full size relay, and the coil side of that will draw more power than the LED would. Its just as easy(easier) to run a small lamp in the circuit, but the relay trick has been around for a while. I use it on bigger trucks and trailers all the time, dont usually recommend it for cars just because its more work, and it often wont fit on bikes.

 

lol ya no i know. it makes sense why it would work, just asking

 

yea i remember those numbers now. thats what i did. idk what the number was for in the middle that i didnt use.
this is the one i got.
http://www.oznium.com/relay40

with the harness to make it easier
http://www.oznium.com/relay-harness

 

87a.

 

sub'd as I'll be getting a trunk without the 3rd brake light.

 

I got a question is there a led 3rd brake light that I can buy to match my led tail lights.

 

for the one in your trunk? idk about that. there is a how to on here somewhere on how to use the LED lights from an impala or something

its pretty hand. good luck, i wanna see yours when you do it