AP500E, AP555E, BG500E and BG555E Asphalt Pavers Caterpillar

Drag Conveyor and Hopper Wings Do Not Operate

Illustration 1	g03396024
Schematic for the Hopper Door Switch

The function of the Hopper Door Switch is to disable the Drag Conveyor and Hopper Wings while the Hopper Door is open. If the Drag Conveyor and Hopper Wings do not function, check the circuit of the Hopper Door Switch.

Note: There is no Diagnostic Code or Event Code that will indicate a fault with the Hopper Door switch or the switch circuit.

The possible causes for the Drag Conveyor and Hopper Wings to be inoperable are listed below:

• The switch has failed.

• There is an open in the harness.

• The ECM has failed. ECM failure is unlikely.

Illustration 2	g03396037
Hopper Door Switch

1. Ensure that switch mounting is tight. Ensure that wire connections are tight. Check that the Hopper Door closes properly to close the Hopper Door Switch circuit.

2. Check the operation of the Drag Conveyor and Hopper Wings.

3. Disconnect the Hopper Door Switch from the machine harness.

4. Connect the Machine Harness connections of the Hopper Door Switch together in order to complete the switch circuit.

5. Check the operation of the Drag Conveyor and Hopper Wings.

6. If the Drag Conveyor and Hopper Wings still do not operate, there may be an open in the switch circuit. Repair the harness or replace the harness.

7. Check the Hopper Door Switch for continuity. The switch should show continuity when pressed.

8. If the switch does not show continuity when pressed, replace the switch.

9. Check the operation of the Drag Conveyor and Hopper Wings.

If the problem persists, the Machine ECM may have failed. Prior to replacing an ECM, always contact your dealership Technical Communicator for possible consultation with Caterpillar. This consultation may greatly reduce repair time. If the cause of the fault is not found and the ECM must be replaced, refer to Testing and Adjusting, "Electronic Control Module (ECM) - Replace".