QUOTE (westpak @ Jan 25 2009, 07:05 AM)
The ECU doesn't process an RPM signal you would have to get an RPM adapter to connect to the 6 ignition wires from the ECU to get the RPM signal.
Another option is probably the little white box behind the AC controls, that box process all of the signals that go to the gauge cluster, I have picked up vehicle speed from there to use on the Fcon so I am sure you can pick up rpm there as well
Tapping one of the ignition wires from the ECU is your best bet. The Unified Meter and A/C Amp, behind the A/C controls, sends rpm to the Combination Meters (speedo, tach, etc.) as a digital word on a communication link. There is no true rpm signal as such.