Dennis would you be willing to help? I work nights and have weekends off. If you could that's be super cool man.
I wired on in on my '85 on the neg side, just a switch, 15 amp rating, and wired in a small light with one leg hot, the ground to the switch. The light came on any time the fan did as if one didn't hear the fan, in 20+ years I maybe used the switch two times but it was rare, not really needed, I just did it in case I ever had the fan not come on? The fan came on automatically when the engine got hot, then temp dropped pretty quick.Why I would control with a relay...! Might be too much load for a simple switch.
I rode a GL1000 for 14 years. Didn't learn much about them....!!.