A quick tutorial on replacing the battery in a GM remote control (part #15186201). These remotes have been used (or are compatible with) vehicles from various GM makes including Saturn, Chevrolet, Buick, Cadillac, GMC, Oldsmobile, Pontiac, Hummer, and Saab. All you need is a quarter, a pencil, and a 2032 button cell battery.

The Energizer 2032 lithium batteries can be found purchased in several quantities:
2 pack: https://amzn.to/2FIKPaw
4 pack: https://amzn.to/2WusWBV
6 pack: https://amzn.to/2V4eEaG