2007 Equinox wiring diagram.

Need help in finding the correct wire (color) and location for the speedometer for my 2007 Equinox. Better yet, what I need is to be able to see or measure the difference in voltage change or timing as my speed increase or decreases. What I would like is to be able to add tap this information via a harness cable within the cab with very little damage to my car.
 
Thanks,
 

Speedometer info is sent thru lan bus on the new lan bus vehicles. Be carefull trying to tie into the wiring of the new lan bus system.

The only place to find this wire without the use of an aditional module would be under the hood at the Tranmission comtrol module. Specifically you will be tapping into the Output Shaft Speed Sensor(OSS). Basically a vehicle speed sensor. your looking for a red wire in pin #2 of connector 3. The TCM is located on the top of the tranny.