Radiator fan switch
 

I installed a 80W RAD FAN and a manual switch in the Roadrunner PUP. Works good, no shock.
I grounded the fan and the toggle. Not sure if I needed to ground toggle.
I noticed some spark action at positive terminal of BATT when I was connecting the lead from fan to BATT,
but once connected, no more spark.
I have a 10A inline fuse to BATT..