If the drivers door is opened with the ignition off and the lamps on, a warning chime will sound. This indicates that the headlamps are still on.
Chevrolet Cobalt Owners Manual. Running the Vehicle While Parked
It is better not to park with the engine running. But if you
ever have to, here are some things to know.
WARNING:
Idling a vehicle in an enclosed area with poor
ventilation is dangerous. Engine exhaust may
enter the vehicle. Engine exhaust contains
Carbon Monoxide (CO) which cannot be seen
or ...