TRANSMISSION GP-DIRECT DRIVE 3590393 - Caterpillar

Illustration 1 g00750050
Schematic for the lamp (action)This diagnostic code is recorded when the main display module reads the voltage of the circuit for the action lamp as above normal. The action lamp is ON CONTINUOUSLY as a result of this diagnostic code. The schematic that is shown above represents a typical installation of the component. Verify the connector contact and wire numbers by using the Electrical System Schematic for the machine that is being serviced. Test Step 1. CHECK THE LAMP CIRCUIT.
Turn the disconnect switch and the key start switch to the OFF position.
Disconnect the machine harness from the main display module.
Turn the disconnect switch to the ON position.
Observe the action lamp.
Turn the key start switch to the ON position.Expected Result:The action lamp is ON.Results:
OK - The action lamp is ON. The harness circuit 421-BU is shorted to the +battery. Repair: Repair the harness or replace the harness. Stop.
NOT OK - The action lamp is OFF. The module has failed.Repair: It is unlikely that the main display module has failed. Exit this procedure and perform this procedure again. Also, recheck if the diagnostic code indicator is illuminated for this diagnostic code. If the cause of the diagnostic code is not found, replace the main display module. See Testing and Adjusting, "Module - Replace". Stop.