Diagnose 4WD System and Wiring Problem

What happens here

The next step focuses on diagnosing the root cause of the non-functional 4WD system. The truck is positioned on an automotive lift to allow for a clear view of its underside. The presenter visually inspects the transfer case and its electrical connections. A critical observation is the presence of inappropriate 'house wiring' (Romex) used to connect to the 4WD solenoid. This wiring is haphazardly routed through the firewall without proper rubber grommets, which is highly suspect and likely the cause of the electrical malfunction in the 4WD system. The vehicle's oil level is checked with the dipstick, revealing it to be about a quart low.

Goal: Pinpoint the likely cause of the 4WD system failure and check oil levels.