Turn signal/flasher relay location

Welcome to 2CarPros.

This vehicle does not use a traditional hazard/turn signal flasher. This function is controlled by the Body Control Module (BCM). Can you explain what is happening?

Let me know.

Joe

Welcome back:

Yep, that is the cause and the way to fix the issue.

Let me know if you have questions or need help. I don't have any technical information on the resistor type needed, but will do my best to help.

Take care,
Joe

As Joe says the only way to get the system to work with LEDs is to add the resistors at every lamp or switch back to conventional bulbs. At the moment the BCM sees the lower resistance as a blown bulb and flashes the lamps faster. I'm surprised it isn't also giving a check bulbs warning for the brake lamps as well.

That makes no difference, they design that in at the factory level. Most do it by adding a resistor to the LED units. Others just program it into the BCM so it knows there are LEDs being used. You punch in the VIN while programming and it downloads the build data from GM and programs the BCM to match the options your vehicle came with. The resistors are the only way to make them work with the existing system.

You're welcome.

The resistors have to drop a lot of current to make things work properly, in the normal incandescent bulbs that is done by the bulbs filament as it uses that resistance to produce light and a lot of heat. The LED's don't need the high current but because of that low current the BCM thinks the bulb has failed as an open circuit and you get the rapid blinking.
Your description sounds like the resistors are the proper value, but the plastic cannot handle that heat close to it. That is common as the heat is normally out in the bulb itself which has a lot of air around it and keeps the socket and connectors away from the heat.
It also is why this is a common problem when adding LED's into a conventional system. The resistors are normally spliced into the wiring in a place where they can get air around them and away from other wires or parts. If I was doing this I would probably opt for parts that are designed as power resistors like those in the image. Something that is the correct resistance but much higher power rating than what is commonly used. The higher rating means they don't get as hot and the case acts to remove the heat generated. So if the resistors you used were say a 5 ohm 2 watt unit, I would find 5 ohm 10 or 20 watt units and use those. They cost more money but they wouldn't cause the problem you have.