Shift Indicator - A/T: Description and Operation

One To Four Light Circuit:

Purpose:
The One to Four light provides a display to the driver, which indicates the transmission should be shifted from first gear to fourth gear for maximum fuel economy.

Operation:
When the ECM enables the 1-4 upshift system, the ECM provides a ground which turns "ON" the One to Four light. The One to Four light will remain on until the transmission is placed into fourth gear, vehicle speed is less than 12 mph or greater than 19 mph or the ECM disables the 1-4 upshift system.

Location:
The One to Four light is located in the instrument panel.