Z71, My Buick on steroids

[Freedom55]

I am having some trouble with the electronic gear selection on my '05 Sierra 4X4 and I am hoping that someone here has had a similar problem and can help me out.

This truck has electronic everything, and everything works, so far. Except the switch to change into 4 wheel mode. Every now and again, the electronics switches the transfer case into 4 low and will not allow me to manually override the computer. This happens when I turn the ignition to start it up and notice that the tiny light has put me into the wrong gear.

I one time had to switch into 4 high to ascend a steep road back up to the highway and it would not shift. Without 4 wheel drive I was stuck on the icy slope and was not looking forward to walking out and flagging down a passing tow truck. What I discovered was that if I held the button down before I turned on the power it would shift into the proper selection and I was out of there. That no longer works.

From time to time I have sat in neutral and I could hear the transfer case shifting when I pushed the button; other times it is stuck in 2 wheel. The fellow at the transmission shop that I trust can't figure out what the codes mean when he plugs it in. I am stumped.

Any experience? I do not want to visit a dealership until I have exhausted all other avenues. Too spendy for a retired guy.

Free (wheeling)

[50/50]

I had the same problem on two pick ups .. I took out the dash selector switch . cleaned the pins and that fixed one of them .. The other I had to touch the 17 watt soldering iron to the terminals . It worked for a week or so then had to replace it. I got one from an auto supply store and not the dealer.

[winger7mm]

I cant remember the fuses off by hand I will look them up later this morning, but if you take out the TCCM fuse, HVAC?, ATC fuse leave them out for an hour or so. Then plug them back in. I have the same issue with my truck sometimes, wont switch to 4Hi but will go into 4Lo. The issue is the TCCM Transfer Case Control Module. It should be located on the passenger side behind the kick panel, search for a different one. As the fuse thing fixes it for now but there is an underlying issue, so it will happen again. Last time it happened to me I just finished cleaning my deer and getting it loaded into the truck at 1030pm, would not shift into 4Hi so I had to use 4Lo to get to the highway, I didnt want to sit there for an hour waiting for the TCCM to reset itself. I hope this helps for now, I will post back in a lol while with the for sure fuses to pull lol