How to locate the ACC wire on a motorcycle?

[DiStephen]

First, turn on the ignition key and use a test pen to identify the live wire. Then, turn off the ignition key and test again - the wire that no longer carries current is the ACC wire. Connect the positive terminal of your device to the suspected ACC wire. When you turn on the ignition key, the device's light should illuminate. If the light turns off when you switch off the ignition key, this confirms it's the ACC wire.

[SanMaria]

As an experienced veteran in car modifications, I have a down-to-earth method for finding the ACC wire: Remove the front cover of the car and trace the wiring harness back from the ignition switch. Set the multimeter to the voltage range, connect the black probe to the metal part of the car frame, and use the red probe to test each wire one by one. When the key is off, there should be no power, but when turned to the ACC position, the wire that suddenly shows 12V is the one. Typically, the wire is black with stripes or brown, but colors vary by brand. If all else fails, connect an LED light to test—if it lights up, you've found the right one. Remember to disconnect the battery before wiring; blowing a fuse due to a short circuit is a minor issue, but damaging the ECU would be a huge loss.