2000 civic tach for gps

im hooking up a pioneer avic d2 and im looking for the tach signal.  where can i find a good tach source??  i tried the blue tach test wire, the blue wire at the distributer, and even one of the wires at the ignition coil... each of them are giving me a tach reading but its not accurate for the gps.  the gps is sensing that the car is moving when its not.  on the gps unit when the car is in park, the accelerator screen shows my car going 3 miles per house and it is counting my distance.. i have the same unit in another car and while in park the speed should be zerp (naturally)  any help/info on this would be greatly appreciated. Thanks!!

blue/white at the cruise control module under the drivers side of the dash. the wire you're looking for is called VSS (vehicle speed sense)Shaughn Murley

Install Manager, Dealer Services

Visions Electronics

Red Deer, Alberta