PLATE 5048694 - Caterpillar

Illustration 1 g01040800
Schematic for the autoshift switchThe following procedure is used to troubleshoot the auto/manual switch. The ECM is always watching the status of the inputs for the auto/manual switch. The inputs have two states: OPEN and GROUND.When the switch is in the MAN position, the MAN input is closed to ground and the AUTO input is open. When the switch is in the AUTO position, the AUTO input (pin 16, 977-YL) is closed to GROUND and the MAN input is open.The possible causes of a problem with the auto/manual switch are listed.
The GROUND input to the switch is not correct.
The machine harness has failed.
The auto/manual switch has failed.
The ECM has failed. This is unlikely.Test Step 1. CHECK THE CIRCUIT OPERATION AT THE ECM
Turn the key start switch to the OFF position.
Disconnect the machine harness from the ECM.