The fan comes with plug that plugs into aux plug that's part of the wiring harness instead of direct attachment to the battery. The fan plug has pos and neg, my 05 superglide harness plug has 4 wires. the harness plugs shows only 10 volts, which is probably why the fan doesn't work with this set up. Has anyone installed the fans using the harness aux plug? Why only 10 volts at the aux plug? I want to use the plug instead of using crimps and direct connection to the battery.
Are you using the Data Link Connector plug? What color wires are going into the pins?
I just installed mighty mites on my 2002 FLH. I have the 4 pin deutsch accessory plug. I moved the red power wire fom position 3 to position 1 on the mighty mite male plug. That position is hot when ever the ig switch is on. I run the mighty mites by using the toggle switch on them. I use the accessory switch on the dash to control running lights. My plug shows 12V.
In short, my fans work fine using the accessory plug. Did you check the plug for corrosion? Does your position 3 (where your red wire is) show 10V when the acc switch is on? Did you have a good ground? I had that issue with mine when I checked it.