All done. I picked up a diesel cluster from the wreckers, and just substituted the tach module. It's just 4 screws.
Some say that you need to run an extra wire, but that's not entirely true. There are 2 wires from the pickup sensor, but one of them is just for GND. I connected the YEL/WHT wire to GND in the engine bay, and the YEL/BLK wire goes to the existing YEL/BLK wire. This works fine.
