Hmm, do you have a multimeter handy?

You can measure how much voltage is present and even the current draw.

But the turn signal bulb has two filaments, one for use as running lights and another for the blinker.

Are you losing both filaments when the bulb goes out?

 

Front or rear bulb ? 3057 is for the rear. Just wondering if you're using the correct bulb.
If the bulbs are correct, next step is to check the wiring. Current draw and continuity of the ground.

 

Not sure if I'm losing both filaments, I know I lose the turn signal.
The bulb I use is 3057 LL.

 

Have you done any wiring changes/additions? Any LEDs involved, markers or license? Is it both sides? I have had less than stellar experience with LL bulbs.

 

Let me try again. Is this a front or rear turn signal we're talking about. 2010 Owners manual lists different bulbs for front and rear.
Yes, the 2 different bulbs are almost identical, but GM must have had a reason for using different ones.

 

The front are supposed to be 3157 and the rear 3057. The difference between 3057 and 3157 is not in the bright filament, but in the dim filament. 3057 has a 2cp dim filament and a 32cp bright filament. The 3157 has a 3cp dim filament and a 32cp bright filament. (cp is candle power)

So, yes; what position are you talking about. There are 4.

 

Rear turn signal 3057 LL

 

There are 2 rear turn signals. Are you paying by the bit?

 

2 pages now and no mention from the OP about checking the wiring. Several have suggested that should be the next step.
Not just looking at it. Test it. Voltage and continuity.

No offense, but this thread is turning into one of those "20 questions" threads. Short little replies without much info is not helping us to help you.

 

I feel like the old days with slow modems and we pai the provider by the byte.

Anyways, I am suspecting after market wiring by somebody stuck in the stone age. And it does make a difference left or right!