Left/Right Rear Turn Indicator Failure

[s5pat]

Little backstory, 2018 Sierra SLT. Came stock with the LED taillights. Opted to swap them out for a pair of smoked non LED taillights, which required a new harnesses. Swapped the harnesses and replaced the taillights. I get L/R Rear Turn Indicator Failure when using turn signals and hyperflash. I get about three normal flashes of the blinker then I get the failure warning and hyperflash. Keep in mind the only LED bulbs in the taillights are the reverse lights. Fuses are good, bulbs look good and all other taillight bulbs work fine. Any troubleshooting ideas before I bring it to the dealer? Could it be the harnesses themselves? Went with ACDelco as opposed to GM harnesses, not sure if that matters at all. 

[s5pat]

**UPDATE** 

 

Hazard lights flash at a normal rate with no failure messages.

[Hillwood]

Put the old lights back in and if they work normal then the issue is with the new lights.. There might be a resistance difference causing the BCM to think there is a failure. 

[s5pat]

There are no old lights. The original taillights are an LED assembly. One connection and a reverse bulb. Could the BCM think there's a failure for the halogen bulbs in the new tail lights pulling too much power since the originals were LED and required less?

[Hillwood]

That is more than likely the issue.. The  BCM monitors the resistance for  flashing and DIC messages..

The manufacturer of the lights you installed should have a solution for this.. 

[s5pat]

I have some LED bulbs on the way. Gonna try to swap the halogens out for LED and hopefully that fixes the issue without resistors.