How do you open trunk of 2005 Chevrolet Cobalt without key?

To open the trunk of a 2005 Chevrolet Cobalt without a key, you can try using the manual release lever inside the car, typically located near the driver's seat. If that isn’t accessible or doesn't work, you might need to use a slim jim or a coat hanger to unlock the trunk latch through the rear seat pass-through, if available. As a last resort, contacting a locksmith or a dealership for assistance may be necessary.