89 Suburban backup light switch

I have an '89 Suburban R1500 with the 700R4 trans. Recently, I noticed that my backup lights don't work. The bulbs are good and my multimeter says that there isn't any power getting to the sockets. I can only assume now that the backup light switch is at fault. Where is the switch, and how do I go about replacing it?

Not 100% sure, but I believe the backup light switch is part of the Park/Neutral safety switch which is located on the steering column under the instrument panel. That's the way is was on the previous generation and the columns are real similar through 1994.