One thing you need to understand: wiring an M-Unit to use the stock handlebar control switches requires several changes to the wiring at the handlebars.
Stock configuration, the switches are passing current across them with
switched power coming to them via the KEY, the Flasher Relay, etc.
For use with an M-Unit, each switch function needs to wire to GROUND on one side, the other side directly to the M-Unit.
Look at the M-Unit. The left side is all inputs. The right side is all outputs. On the left, the MU seeks a signal from a ground trigger. When it does, it passes internally to the right, switching power momentarily to that circuit, and sends power
directly to the component skipping the handlebar switch altogether. This is more efficient in some ways, and limits the switches from causing shorts as all of that is within the MU.
You can also use much smaller wire gauge from the switches to the MU. And you can use smaller wire from the MU to the components. I use 22awg input, 18awg output.
If you look at the PDF I attached, you can see the routing of what I describe above more clearly. You no longer need the stock Flasher Relay as it’s incorporated to the MU.
Hope this helps provide some additional explanation as you undertake your wiring job.
