Okay, so I had this 2002 Sportster, and I wanted to add some accessories, like heated grips and a USB charger. The problem? I didn’t want them draining the battery when the bike was off. I needed switched power – something that’s only on when the ignition is on.
First, I grabbed my trusty multimeter. Gotta find a source, right? I started poking around the headlight bucket – it’s usually a good place to find wires.
Finding the Right Wire
I popped off the headlight and started looking at the wiring harness. There were a bunch of wires, all different colors. I knew I needed to find one that was hot only when the key was turned on.

- I turned the key to the “on” position (but didn’t start the engine).
- Then I used the multimeter’s probe to touch each wire’s connector, one at a time, while grounding the other probe to the frame.
- Most of them showed nothing – zero volts. That meant they were either ground wires or only got power when the lights were on.
- Finally, I found one! The multimeter jumped to 12 volts. Bingo!
- I double checked,I turned the key off. The multimeter went back to zero. Perfect – that’s switched power!
I think It may be an orange and white wire,but I forgot the real color,you have to find it by youself,I can’t remember.
Making the Connection
Now, I didn’t want to just splice into the wire. That’s messy and can cause problems down the road. Instead, I used a Posi-Tap connector. These things are awesome – they let you tap into a wire without cutting or stripping it.
I carefully attached the Posi-Tap to the wire I found. Then, I ran a new wire from the Posi-Tap to a small fuse block I mounted under the seat. This fuse block became my new distribution point for all my accessories.
Wiring the Accessories
From the fuse block, I ran separate wires to my heated grips and USB charger. Each accessory got its own fuse, just in case something went wrong.
I made sure all the connections were solid and used heat shrink tubing to protect them from the elements. I also tucked all the wires neatly out of the way, using zip ties to keep everything secure.

Testing it Out
With everything wired up, it was time for the moment of truth. I turned the key on, and… success! My heated grips started warming up, and the USB charger showed it was getting power. I turned the key off, and they both shut down as expected.
It took a little bit of time and patience, but now I’ve got switched power for my accessories, and I don’t have to worry about killing my battery. And It’s all pretty clean and organized, too. If I ever need to add more accessories, I can just wire them into the fuse block.
And Now,I can go anywhere I want.