3rd brake light always on

obs7.3 · Jun 13, 2012

I put in a LED third brake light and cargo light and had to splice it into the stock wiring in the roof. but whenever my truck is running the 3rd brake light is always on. it gets brighter when I step on the brakes. it's like i tapped it into the parking lights or something (but this is the only light that's on whenever the truck is running) but I checked the wires and there's just the 3 power wires and 3 grounds.
i'm not sure if the stock third brake light did the same thing or not cuz the bulb was blown in it when i swapped it out but i never noticed it before the bulb blew.
has this happened to anyone else? where could that harness in the roof to be getting power at?

baderic03 · Jun 13, 2012

you put a resitor in line for the led

obs7.3 · Jun 13, 2012

i need to put one in or i did by going to LED?
sorry, electric isn't my forte.
if i need to put one in, which one do i need?

baderic03 · Jun 13, 2012

I believe you may need too

obs7.3 · Jun 14, 2012

alright. thanks

old man dave · Jun 15, 2012

Apparently some of the LED light vendors sell resistor kits to fix this problem. The LEDs draw a lot less current and fools the control circuitry. Don't know what value of resistor though. Try having this thread transferred to the aftermarket electronics/lighting forum.