Hey Scotty, my 05 Chevy Suburban has a Service 4x4 light come on at random times and sometime changes in to different 4x4 setting without me pushing the switch. I have Replaced the encoder motor and the 4x4 dash switch in the last year. According to the code, these would fix it. Any other ideas?
Codes only give a starting point, not the exact fix. On any vehicle you have to check all the interconnecting wiring.
Common finds are...bad grounds that cause random poor connections, pinched or abraded wires that intermittently short out, damage from rodents chewing insulation or urinating on wiring connections, road salt destruction that can travel internally in wiring for feet. Crazy wiring of aftermarket stereos, remote starters, and alarms. Water damage in fuse boxes.
Continuity meter or ohm meter checks are ways to find compromised wiring.
I've got a compact tractor in my shop now that has been to the selling dealer and another shop that couldn't find it's electrical issue. I found a mouse nest that destroyed part of the main wiring harness hidden deep in the dash.
Don't quote me, but maybe the transfer case is bad?
I vote for checking the grounds. Chevys are notorious for rusty ground mounting locations that cause all kinds of weird, intermittent problems.
