2001 Buick Century Owner's Manual - Page 86

To replace the battery: 1. Insert a flat object like a dime into the slot on the back of the transmitter. Gently pry apart the front and back. 2. Remove the old battery and replace it with the new one. (Use type CR2032 or an equivalent.) Make sure the positive (+) side of the battery is facing down. Do not use a metal object to remove the old battery. 3. Snap the top and bottom together, making sure the halves are together tightly so water won't get in. 4. Test the operation of the transmitter with your vehicle. 2-16