Installed GTR LEDs w/ Canbus... but still need resistors?

DENALIHD66 · April 8, 2021

So according to the descriptions, these LEDs when installed in turn signals and brake lights (as turn signals) they do not require load resistors because it is built in. I installed all 4 into my 2015 GMC Sierra taillights. The bulbs will work in either direction (despite it saying polarity specific), and the 4 way flashers and turn signals work fine when only the accessory power is on. The story changes when the truck is running, and when using the turn signals, I experience hyper flash accompanied by a DIC error that the taillights are failing. I haven't yet installed the front bulbs yet, but before I tear apart the front end to get into the lights, I wanna know if these are still going to require resistors to work and prevent hyperflash.

Otherwise, the light output is great and they look much better than the factory halogens. I also replaced the side marker lights with LEDs.

These are the bulbs I got. GTR Carbide Canbus (white). https://www.theretrofitsource.com/7440-7443-gtr-lighting-carbide-bulbs-LED.BUL.7443.CAR2?quantity=1

In the event I am going to need resistors, what do you guys recommend and how many do I need? Since my truck has 2 tail lights that flash per side, do I only need to tap one of the bulbs or do I need a resistor for each bulb?

Also came across these that fit the 7440 bulbs, would these work instead?

https://www.summitracing.com/parts/put-240007

Really dont like the idea of t-tapping exterior wires if I don't have to.

J.H.2015LT · April 8, 2021

I installed the GTR Carbide 2.0 bulbs as well. You will need one resistor for each bulb. These are the resistors I used:

https://www.headlightrevolution.com/closeout-resistors-capacitors?quantity=1

Edited April 8, 2021 by J.H.2015LT

DENALIHD66 · April 9, 2021

Can anyone weigh in on the Putco plug and play resistors I posted about?

DENALIHD66 · April 17, 2021

So TRS sent me load resistors to be installed with the bulbs. All the youtube videos I find consist of the person saudering the wires together instead of using the T-Taps. From what I gather, its the outer 2 wires leading to the bulb that you want to deal with, but as far as how the resistors actually connect into them with the T-Taps, I can't seem to find anything that shows how they need to be installed. The kit comes with Red and Blue colored T-Taps, is there a difference between them? I couldn't find anything on youtube or even this site with a search.

DENALIHD66 · April 18, 2021

I got 6 resistors from TRS. I got the tails installed and they work fine. I did the exact same setup using the same color wires for the front turns but they still hyperflash and throw an error in my DIC. Is there something I am missing for the front ones?

The rears I used the two outside wires (black and green) to tap into. The fronts the wiring configuration is slightly different but I used the same black/green combination. The 3rd wire was off white in color.

Edited April 18, 2021 by DENALIHD66

Joppy818 · April 19, 2021

What kind of Sierra did you have do you have DRL?

DENALIHD66 · April 19, 2021

2015 GMC Sierra 1500 SLT. Yes I have the DRL bars on mine. I called TRS and they are saying adding resistors to the leds with built in canbus can also be a reason they are still hyperflashing... so they recommended a different bulb. Since the rears work, I guess I'll just swap out the fronts for the non-canbus ones and keep my fingers crossed?

Joppy818 · April 19, 2021

resistors solved my problem with hyperflashing.

DENALIHD66 · April 19, 2021

27 minutes ago, Joppy818 said:

resistors solved my problem with hyperflashing.

I have the resistors installed and they are still hyperflashing. I have them connected to the green and black wires on the front turn signals. The rear LEDs work fine with them. I need help figuring out the fronts. There is nothing available online or anywhere that I can find that confirms how they should go on the front turn signals.

Joppy818 · April 19, 2021

I can check mine and let you know. I also have diode boards I dont know if that matters. If everything just piggy backs on the parking lights?

DENALIHD66 · April 19, 2021

18 minutes ago, Joppy818 said:

I can check mine and let you know. I also have diode boards I dont know if that matters. If everything just piggy backs on the parking lights?

Yeah I only have 3 wires going into my front turn light. I used the green and black ones. The 3rd one I think is white in color but I didn't use that one. At first they worked, but after about a minute they stopped and went to hyperflash.

15BlueSilverado · April 19, 2021

On 4/17/2021 at 6:26 AM, DENALIHD66 said:

So TRS sent me load resistors to be installed with the bulbs. All the youtube videos I find consist of the person saudering the wires together instead of using the T-Taps. From what I gather, its the outer 2 wires leading to the bulb that you want to deal with, but as far as how the resistors actually connect into them with the T-Taps, I can't seem to find anything that shows how they need to be installed. The kit comes with Red and Blue colored T-Taps, is there a difference between them? I couldn't find anything on youtube or even this site with a search.

The red ones are for thinner gauge wire and the blue ones are for a slightly thicker gauge, there are also yellow ones available that are for even thicker gauge wire. They have their pros and cons just like everything else out there, it just depends on whether or not you want to go back and replace them after a while since they'll be prone to the elements and the small metal inserts can/might rust causing connection issues.

DENALIHD66 · April 21, 2021

SOLVED. So the front turn signals are a bit different than the wiring on the taillights. There is green, black, and yellow. I originally copied what I did to the taillights (tapped into the black and green wires) but I ended up changing the fronts from the green and black to yellow and black and now they are working. The resistors were getting hot so I know that it was the right one. Wondering why the taillights worked differently unless its because they also have to function as the brake and then that would explain it when its brighter.

Very happy with the light output, definitely a huge difference.

Edited April 21, 2021 by DENALIHD66