I have a Z71 with pushbutton 4WD and the 4WD selector switch doesn't work right. on 1996 Chevrolet 1500 Pickup

The LEDs don't light or flash when the ignition is turned on and the transfer case doesn't reliably shift when the buttons are pushed. Sometimes I can remove power from the PCM and the switch will flash once and transfer case will work once.

Asked by for the 1996 Chevrolet 1500 Pickup