Did one in a '85 a while back. You have to take the gauge cluster bezel off, then the small bezel around the headlight and wiper switch. The wiper knob just pulls off, and there's a small button on the bottom of the switch you press to pull the headlight knob out, it's kinda hard to get to up under the dash but not bad.

The hardest part for me was trying to unclip the plug from the top of the switch, there's not much of an opening to work through, and the wires are pretty short.