2013 Silverado crew cab

 

Replace it! I have taken these apart before very carefully and cleaned the contacts and they started to work again.

 

It's a known issue that they're not very well protected against water ingress. Going to drive-thrus in the rain, opening the door in a heavy storm, etc. will allow moisture to get in and the switch contacts get corroded.

You can either buy a replacement or troubleshoot your existing unit and try to clean it up. Personally, I don't have the time to mess around with that kind of thing. I'd just buy a replacement.

 

How do you know it's the switch. Could be a break in the wiring near the door hinges. They flex every time the door opens.