Both sides have switches in them. And yes there behing the c pillar too.

BTW, Depending what car, u got 3 pillars. A B C (although hatches have D too)

The pillars are what "joins the roof" to the rest of the car. So a-pillar is at the front. B, between the doors, C behing the read door. And thats it for a sedan, but a hacth has D right at the back.