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Overhead has one display mode that is blank, display off. Try pushing only right button to change modes.
Does your VIC display change when you shift between HI and LO range? If not, switch connector at t-case might be bad/unplugged. Or switch could be bad.
VIC might have bad internal solder joints causing 4wd switch message and memory loss (or real loss of battery power occurs).
If PO grounded the VT/YL wire to defeat alarm, remove the ground, then see if your 30 second delay stops.
Since you have a few different problems, make sure battery cables/connections are clean and tight on both ends.