Hi everyone, I have a 2000 GMC Sierra Z71, 5.3L engine,and pushbutton 4wd. I was having a service 4wd message coming up on my display. I could switch from 2hi to 4hi but once i switched it would get stuck in whatever positon i last pressed. So I had the codes ran it it only came up with one "selector module error" . So I changed the selector switch module,and this took care of my problem of getting stuck in 2hi or 4hi. But when i put my truck in neutral and try to go to 4lo the light flashes for about 30 sec and then goes back to whatever mode it was in. I noticed that the light on the dash lights up for park and every positon except for neutral. is this the encoder sensor or does anyone have and suggestions to what is causing this problem?