12. To hookup the tach, the GMR pickup needed to be tapped into the green/yellow wire for the coils. The GMR is fitted with green, red, and black wires inside the thicker gauge gray wire. For this model, the green was tapped into the pink of the TWH, which sends a signal to the tach gauges through the coils. The red was tapped into the brown on the tach harness, which goes to the Factory Tach Plug (FTP). And the black (ground) from the GMR goes to the black/green (ground) from the FTP and the black of TWH.