trail tech taco

wtf is a taco? you going mexi on us?
i think you mean a tach. as in trail tech vapor tach
Vapor Digital Gauge at Trail Tech Home

but if you got it new, they should give you instruction on how to wiring it up.
but best place to work the power wire would be on the on/off switch's power wire.
for the tach, you have to wrap the wire around your coil wire.
 
yeah, chill, we all have cabin fever here, now you owe us one