Silicone grease on weatherstrips will make them last longer, seal better, and not stick or squeak. Apply silicone grease with a clean cloth. During very cold, damp weather frequent application may be required.
See Recommended Fluids and Lubricants.
Chevrolet Cobalt Owners Manual. Door Locks
To lock the driver door from outside the vehicle, turn the
key clockwise. Turn it counterclockwise to unlock.
The Remote Keyless Entry (RKE) transmitter can also
be used to lock or unlock the doors.
From the inside, use the manual lock knobs on each
door or use the power door locks.
Power Door ...