coolent sensor connector to big

[dmarr35]

Why is it that my 2012 sonic 1.8 coolent sensor connector is bigger then the coolent sensor I tried all part stores they can not figure it out purchased

Sensor 55591401 213-4688 and​

213-4688 GM Automotive Engine Coolant Temperature Sensor ‎55591002 55591401 all to small and when the parts places bring up the sensors too small they can not find the size I have in the termostat housing​