OK having done some research on LIN bus, and thinking about it in the context of the GS WC it seems to me that:
- The LH Switch is a bunch of mechanical switches that connect to GPIs on an integral LIN bus slave unit that digitises the operation of a mechanical switch. The Wheelie thing is merely another bunch of mechanical switches that connect to the same LIN bus slave unit.
- Operation of one of the switches will pull one of the GPIs to +12V. So Switch-1 will pull GPI-1 high, Switch-2 will pull GPI-2 high etc. The pulling of each GPI to high is detected by the LIN bus slave, digitised, and transmitted as a message over the bus.
- The 3 wires that leave the Switch are a pair of wires for the LIN data bus (it's differential) plus a switched power source from the bike.
The Wheelie thing puzzles me as to why it has 6 wires. IIRC the Wheelie thing offers four functions: Spin Up, Spin Down, Switch Left, Switch Right. One wire for each function plus another wire for power, and that makes 5. Unless there is a 6th Wheelie function that I can't think of, perhaps the 6th wire is redundant?
So my thinking so far is that you could perform mechanical switch operation reassignment without touching the LIN bus side of things, by modifying the wiring of Switch-1 so it is connected to GPI-2 as opposed to GPI-1. I also think this can be achieved by butchering the LH switch gear & Wheelie thing alone, which is not that expensive to replace if it goes Pete Tong.
When I get some time I will remove my LH Wheel & LH Switch gear and have a poke around inside it and a play with a multimeter.