Two-Wheel-Drive TACO? (4x4 Not Engaging, Flashing 4WD-4LO: '06 Tacoma)

This MINT 2006 Toyota Tacoma 4x4 4-cylinder stick shift truck has one annoying problem: It's STUCK in 2-WHEEL-DRIVE, and snow is on the way! The "4WD" and "4LO" indicators are constantly flashing on the dash. The owner has done MONTHS of research and repair attempts, but he brought it to PHAD BEFORE firing the Parts Cannon :) Let's diagnose the problem and see if we can get this Taco back into "WINTER 4x4" mode before the snowstorm hits!! ASTRO DVOM: https://www.amazon.com/dp/B07FDBW1PT?... AWESOME TEST LIGHT: https://www.amazon.com/dp/B000M5ZWBA?... TS 101 POCKET SOLDERING IRON: https://www.amazon.com/dp/B07SQDZ9SV?... Enjoy! Ivan