I realized that the side mirror turn indicator lights on my corolla don't seem to be working when I use my blinkers.
The only time I see them light up is when I lock and unlock my car.
Its similar to your parking light and turn signal bulb. When one side of the bulb breaks, the other side still functions until it breaks. It is a combo bulb. 2 functions in one bulb.
question. when i am sitting in my car and use the turn signals, i do not see the side mirror signals blink, but when my mirrors are folded, i see them when i signal. dumb question, but have you had someone stand there and watch to see if they aren't working when you throw the switch?
since your car is within 3 yrs and under mileage, you should have the dealer take a look under warranty..
hopefully i'm not sounding like a jerk. it is hard when typing to not sound one way or anohter.