Ford F-150 4WD Transfer Case Selector Switch FL3Z-14B166-DA

This is the dash-mounted 4WD selector switch for the 2015-2020 Ford F-150 with the 4A (Auto 4WD) system, replacing Ford FL3Z-14B166-DA. The rotary knob selects 2H, 4A, 4H and 4L, and pulling the knob out requests the electronic rear differential lock. It does not fit the 2012-2014 F-150 switch CL3Z-14B166-DA, or the FL3Z-14B166-AA and FL3Z-14B166-BA switches used on trucks without 4A.

A failing selector switch sends the wrong signal, or no signal, to the 4x4 control module. Symptoms are a knob that does nothing when turned, a truck that will not shift between modes or only works intermittently, the 4x4 indicator not matching the knob position, and a 4x4 warning message on the cluster. Because the transfer case shift motor, its encoder and the wiring can cause the same complaints, scan the 4x4 control module for codes and check the related fuses before replacing the switch. If you can hear the shift motor run when you change modes, the switch is probably working.

To replace it, turn the truck off, carefully release the trim around the switch with a plastic trim tool, and pull the switch out far enough to reach the connector. Unplug the old switch, plug in the new one, and snap it back into the dash. Start the truck and test each position, including 4L in Neutral and the rear locker pull, and confirm the indicator follows the knob.