Still working on wiring this 79. I don't have much of a wire trail to follow, thanks to the packrats mentioned above. Does the heating/cooling fan have a relay switch? If so, where is it?

I am restoring a 79 F250. I drove it in high school and the motor finally shelled in 1998. It sat in my dad's windbreak for a few years and a packrat made a home out of it and absolutely destroyed my wiring. I bought a Painless harness and am struggling to get that installed, but am slowly...