The vehicle has a battery saver feature designed to protect the vehicle's battery.
When any interior lamp is left on and the ignition is turned off, the battery rundown protection system automatically turns the lamp off after 20 minutes.
This prevents draining of the battery.
Electric Power Management
Accessory Power Outlet(s)Chevrolet Cobalt Owners Manual. Engine Coolant Temperature Warning Light
This light comes on briefly
while starting the vehicle.
If it does not, have the vehicle serviced by the
dealer/retailer. If the system is working normally
the indicator light goes off.
Notice: Driving with the engine coolant temperature
warning light on could cause the vehicle to
overheat. ...