Diesel Data: Automotive Repair

Shift Light: Testing and Inspection

M/T Shift Light Check:




Chart C-8 Wiring Diagram:







CIRCUIT DESCRIPTION:

The Shift-Up Light (Shift Light) indicates the best transaxle shift point for maximum fuel economy. The light is controlled by the ECM and is turned "ON" by grounding the Lt. blue wire from the light to the ECM. If the Lt. blue wire is grounded the lamp will be "ON" all the time. If the circuit is open the lamp will not be "ON" when commanded by the ECM.

TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. This should not turn the shift light "ON." If it does, the Lt. blue wire is shorted to ground or the ECM is faulty.

2. This checks the shift light circuit up to the ECM connector.