Join Date: May 2006
Location: Gainesville, FL
This is what I got from the autometer site.
Tachometer Signal Wire Installation
for 3.8L engine(s)
Must use model number 9117 Auto Meter tachometer adapter. Locate the large, square 42 pin wire harness connector in the corner of the engine bay where the passenger fender meets the firewall. Pop the plastic cover off of the top of this conector to expose where the wires enter the connector and to expose the wire pin numbers. Locate pin number 34 which will be in the corner of this connector and will be either a red wire or a red with a green stripe wire. Cut this wire in half so that you now have two cut halves. Hook the red of the adapter to the cut half coming from the connector. hook the red/green of the adapter to the other cut half. Ground the black wire of the adapter. The gray wire of the adapter will now provide you with a good tachometer signal.