I have a '05 Silverado and the Service 4wd light is on. Chevy did a diagnostic and it came back as no connection to module. From reading around I've read that is it sometimes the selector switch so I replaced that and that wasn't the problem. I was shopping on amazon and came across this Dorman 600-120 Transfer Case Motor Encoder Ring.

From reading the reviews people said this solved the problem and it's way cheaper than the transfer case module which is $200.

Has anyone ever replaced this and solved the problem?

Thanks