3 lights above rear window

Hello, I honestly do not know, not being familiar with that particular vehicle. But you can get your answer by addressing your owners manual! Try there. If you don't have one, acquire one by performing a web search.

In the past - some GM vehicles used similar lamps for rear bulb functionality confirmation - - looking at these lights - turn signal light on - yellow light should blink on same side - depress brake - red light should turn on. However as mentioned - the owners manual should offer a more detailed explanation.