Jack,
I'm assuming that after you replaced the relay, the fan is still erratic. Attach another wire to the terminal on the thermostatic switch. Leave the original wire on. maybe use an alligator clip, or just wrap a wire around the terminal if you can. Make sure the wire is long enough to reach a known good ground. (hopefully the fan is cycling on and off erratically when the bike is sitting still, idling.) When the fan goes off when it's not supposed to, touch the extra wire to ground. If the fan comes on, the thermostatic switch is bad. All the switch does is provide a ground to the relay. You can test it by heating it in water, but that's a pain in the ass. Might just as well replace it. Good luck!! ............Don B
I'm assuming that after you replaced the relay, the fan is still erratic. Attach another wire to the terminal on the thermostatic switch. Leave the original wire on. maybe use an alligator clip, or just wrap a wire around the terminal if you can. Make sure the wire is long enough to reach a known good ground. (hopefully the fan is cycling on and off erratically when the bike is sitting still, idling.) When the fan goes off when it's not supposed to, touch the extra wire to ground. If the fan comes on, the thermostatic switch is bad. All the switch does is provide a ground to the relay. You can test it by heating it in water, but that's a pain in the ass. Might just as well replace it. Good luck!! ............Don B