the first step is to remove the headlight switch knob, to do so use a small flat screw driver to depress the metal tab located inside the groove of the knob, pull on it at the same time and remove it from the switch.
Pry gently on the two instrument panel moulding pieces located on each side of the steering column and remove them from the dash as shown on the image.
Remove the two screws that were hidden behind the two pieces of trim you just removed.
Gently pry the dash out, unplug the fuel tank selector switch electrical plug and remove the Instrument cluster finish panel.
Remove the headlight switch retaining nut.
Remove the two headlight switch mounting bracket screws and set the bracket aside.
In the truck we are working on the headlights worked but the tail lights didn't, we tested for power coming out of the switch ( brown wire, see image ) when turning the parking lights on and there was no power coming out due to a bad contact inside the switch.
NOTE: Make sure that you test all your fuses before performing this test to make sure that your problem relies on a bad switch and not a blown fuse.
Unplug the electrical plug from the old switch and replace it with the new one, if the new switch didn't come with the lever remove the lever from the old switch by depressing the metal button located on the opposite side of the electrical connector and pull the lever out, to install it on the new switch just press it in till you feel a click.
Operate the switch to make sure that all the lights work, if the lights work properly proceed to install the remaining items in the reverse order they were removed.