The most important thing is spraying the door lock and handle with WD-40 from two locations:

A) Space between the handle and door.
B) Side blind plug (again you will find it on the side of the door)

Usually I do that frequently, the whole idea that spraying WD-40 will replace the moisture inside the carrier and especially the cable.

After doing that you will place the grease as shell to decrease the water that goes in.

I hope that will help , with me it reduced the frozen handle chances by 99%.