My 4x4 is working off and on and it only quits working when you shut the tahoe off and crank it back up. The dealer said it was a corroded fuse because it started working when they wiggled it. All was good for 4 days now its doing it again. I put a new fuse and no change. I put a dorman tccm in it and nothing changed so I put the factory tccm back in. HELP