Chevrolet Repair: 4WD push buttons, gm tech 2, silverado z71

Question
2005 1500 Silverado Z71 5.3 Engine 4WD Clubcab 410 posi. rear
Sometimes when starting truck, lights on push button 4WD do not light. When this happens you can not shift transfer case. Next time you start truck, neutral or other light may come on. Then you can shift transfer. Sometimes after several miles traveled, turn ignition off, and restart, 4WD lights function and everything is normal
Any ideas or help would be appreciated
Thanks, Keith

Answer
HI KEITH, THERE IS A 2 X4 SWITCH ON THE LOWER SECTION OF THE TRANSFER CASE SOMETIMES THESE WIRES CORRODED TO THIS SWITCH AND CAUSE THIS TYPE PROBEM. CK THAT OUT FIRST BEFORE BY NEXT IDEA WHICH IS YOU ARE NOT GOING TO LIKE THIS BUT, THIS IS CONTROLLED BY A TRANSFER CASE 4WD MODULE..THEY DO FAIL..BUT BEFORE JUMPING TO THIS THE BEST WAY TO FIND OUT FOR SURE IS TAKE IT TO A SHOP THAT HAS GM SOFTWARE OR A GM TECH 2 SCAN TOOL..THIS TOOL CAN GET IN THE SYSTEM AND DEMEND IT TO TURN ON 4WD HIGH, LOW, NEUTRAL AND SO ON. SO IF THE MODULE WILL DO THIS THEN THE MODULE IS MORE THEN LIKELY OK.THIS TRUCK ALSO HAS A TRANSFER ENCODER MOTOR AND SELECTOR SWITCH. THIS IS NOT LIKE THE OLD DAYS WITH A MANUAL SHIFTER ON THE FLOOR FOR THE TRANSFERCASE. SO BEFORE YOU GO OFF SPENDING LOTS OF YOUR HARD EARNED MONEY ON GUESSES IT IS MUCH CHEAPER TO GET THIS SCANNED TO KNOW FOR SURE..WITHOUT A SCAN YOU WILL BE LOST. I HOPE THIS HELPS YOU AND GOOD LUCK,,TOM