So the other day I was letting the bike idle in the driveway. I was waiting for the fan to cycle since I hadn't seen that work yet. I waited, and waited, and waited, and finally chickened out just as the temp needle got to the top of the white range on the gauge.
I started poking around with a meter a bit.
Grounding the fan switch lead triggers the relay.
The relay provides 12v to the fan connector when it's activated. Fan doesn't run though. Hmm.
Hooked the fan up to straight 12v, and the fan runs.
Hmm. Gotta be a ground issue.
With the ignition key "Off", I get continuity from the black wire on the fan connector to the battery -, and for that matter, every other ground point I can find.
With the key off, every black/yellow ground wire I probe is a dead short to battery negative. Good.
As soon as I turn the key on though, the fan ground, along with every other black and yellow ground wire, shows 580 ohms of resistance to battery negative. That's why the fan won't run, crap grounding.
Also explains why the turn signals only barely work, and the headlight noticeably dims when you hit the brakes.
You need to check the chassis wiring harness ground up near the brake light assembly. All of the low amp accessories are ground through the harness to a single point up there. I'd be really suspicious of that 2 pin connector just above the chassis ground pigtail. That was a stupid dumb ass connection where the main harness is connected like that rather than straight to a wiring eyelet and the ground from the brake light could have been an eyelet to the same chassis ground point.
Pic is a cut and paste from the wiring diagram right hand side middle of diagram.
One of the best tools I ever made was to copy the wiring diagram from the electronic manual and take it to Staples Business Depot and got them to explode it to 11" X 17" and then laminate it. When I have electrical gremlins to hunt down I use the larger drawing and mark it as I go along with dry erasable markers. When I'm done, just wipe it off and hang it on the wall as wall art. Most people who come in to my shop see it and think it's a great idea. Easy to follow and now it's your handy dandy go to when the electrical problems show up.