I think you need an additional harness to set up the rev specific boost or maybe it's for the speed? I've got one with the extra harness but never set up the speed/rev specific boost. The speed reading isn't too accurate either - it jumps about, wildly! My top speed recorded is something like 32,564kmh! The rev counter is ok though, as Shorty said there is a pin out diagran somewhere if you search. The easy option is the optional trigger switch thing: It's much easier to setup.