Wiring help need for taillights

Correct. When wired to the truck and the running lights are on I have no action on the brake and turn. The front turn signals and 3rd brake light work fine. When the running lights are off the brake and turn function normally.

When I use an external power source to the Brake/Turn input with the running lights sourced from the truck I get function.

Something about the running light source from the truck seems to be causing the issue but I can't see why. I light tested all.of the inputs before and after the converter box and everything functions except the fainter turn signal out after the box on one side for some reason.

 

Sorry for not being clear. I was using 2 separate batteries seperate of the truck to make sure that the lights do work and the Brake/Turn action will work while running input has power.

 

It sounds like you are running all of the wires into your conversion box.
On the truck side of the box, separate each blinker from the brake wires.
Using

$12 CURT 58240 Non-Powered 3-to-2-Wire Splice-in Tail Light Converter, Not Compatible with LED Lights

this convertor box substitute the trailer for your LED's
The stock tail light wires go directly to the running/tail connection on the LED's,
Take the left turn signal wire and connect it to the left (yellow) input on the box.
Take the right turn signal wire and connect it to the right (green) input on the box.
Take one, or both brake wires, and connect to the brake (white) input on the box.

Off of the box, the trailer side;
Take the yellow wire and connect it to the stop/turn connection on the left LED
Take the green wire and connect it to the stop/turn connection on the right LED
Ground the LED's to the frame as you have done.

I haven't used the box referenced earlier, but it looks like the running/tail wire from the truck would go to the brown on input, and output brown to your tail lights, brake (without turn signal) would go to red, and the right turn to green, and left turn to yellow and the ground through the whites. the ground, and tail lights just go straight through, and the conversion/combination happens in the box via circuitry for the yellow, green, and red.

 

Thanks for input. I'm using a similar Box and verified correct wiring. I was able to get more Turn/Brake response by wiring 2 6 Ohm resistors in series to the running light input confirming my suspicion that the running lights are washing out the turn signal. I suspect that there is some electrical bleeding into the 2nd set of leds.

It's still not where I'd like it to be as it's not going to be as noticeable during the day if I have my running lights on so I'll likely play around with the amount resistors until I get the right combination.

Edit. Nope washout isn't the problem. I can power both functions from seperate power sources seperate from the truck with perfect function. Back to the drawing board.

 

Alright so I don't think this resistor idea is going to work unfortunately. Given the amount of resistors needed and the heat and durability issue I think I'll scrap that idea.

Is there any possible way to cut the driving lights to a given LED light when the turn and brake signal is sent to the light? Not sure if it'll be worth the hassel. I really like the simplicity of the 4 4" leds in the back but I'm tempted just to wire in dedicated turn signals.

 

make sure the trailer harness you bought is compatible with LEDs, most are not by default and will cause bleed (just making sure). There are also "powered" and "non-powered" versions of harnesses, get the "powered" one as it will have it's own source of 12V from the battery

also you could just "skip" wiring the "run" function through the box and have it direct to the LEDs and see if that works or not?

also to correctly make your thought work you need diodes and relays to cancel out circuits, not really worth the hassle

dedicated turns along the slant of the rear with slim oranges would be kinda cool

 

Bypassed the running light input directly to the taillights without much success. I ordered another 3 to 2 coverter box that's supposed to be led compatible so hopefully that solves the issue. I'll keep ya updated! Thank you so much for that input.

 

Problem solved! The coverter box wasn't led compatible. Replaced it with one that was and everything is working like it should.