This is the original wiring guide for the
Thunder Mfg switch which is basically a
HD softail switch (there even a how to
do it on the cheap.)
DO NOT WIRE YOUR SWITCH THIS WAY!Here's why.
This is how the stock switch works. Tail1 and Tail2 connect to each other in the ON position not the directly to the Battery(12V+ White Fuse at 30Amp).
Then a plug switches the Blue to Red/Blue and it goes to the fusebox. The Red goes straight the taillight bulb.
The Red/Blue(Blue) wire should be fused(10Amp) and feed the taillight.
So if you wire it like the original Thunder diagram, then white wire will feed the red tail light without the 10Amp fuse for it. Yes, the stock park position works that way, but you're not bouncing down the road in that position.
So if you use a switch a Harley/Thunder switch, then just permanently connect the Red/Blue(Blue) to the Red. The taillight will work fine. You won't have a park position, but you will have a taillight fuse.
Also that resistor on the Gray wire is very important, too.
100 ohm Radio Shack P/N 271-1108 (Card of five).