Test I: Range Selector Display Inoperative Or Displays Incorrect Range (4L80E Diesel): Description
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2001 GMC Savana Special, 2001 GMC Savana Camper Special, 2001 GMC Savana, 2001 Chevrolet RV Cutaway, and 2001 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
Transmission Range (TR) switch is part of the Park/Neutral Position (PNP) and back-up light switch assembly, which is externally mounted on transmission manual shaft. TR switch contains four internal switches which indicate transmission gear range selector lever position. Instrument Panel Cluster (IPC) supplies ignition voltage to each switch circuit. As gear range selector lever is moved, the state of each switch may change, causing the circuit to open or close. An open circuit or switch indicates a high voltage signal in the IPC. A closed circuit or switch indicates a low voltage signal in the IPC. IPC detects selected gear range by deciphering the combination of voltage signals.