3508, 3508B, 3508C, 3512, 3512B, 3512C, 3516, 3516B and 3516C Engines Caterpillar Monitoring System Caterpillar

The Alarm Silence Switch Does Not Silence The Alarm

This procedure is for the Alarm Silence switch that will not silence the Alarm. The "Does Not Silence" condition is probably caused by an undesired open circuit. Also, the Main Display Module may cause the problem (unlikely condition).

1. Locate The Switch.

   1. Turn the "ECS" switch to the OFF/RESET position.

   2. Locate the Alarm Silence Switch. If necessary, use the Electrical System Schematic to assist in locating the switch.

   3. Check for loose terminals or corroded terminal connections to the switch.

   4. Clean corroded terminals and tighten loose connections.

2. Check The Harness.

   1. Disconnect the signal wire from the Alarm Silence switch.

   2. Turn the "ECS" switch to the OFF/RESET position.

   3. Ground the signal wire from the Alarm Silence switch.

      Expected Result: The Alarm should become quiet.

      Result:

      • OK - The Alarm becomes quiet. The circuit is operating correctly. The switch has a problem. Check the switch or replace the switch.

      • Not OK - The Alarm does not become quiet. The signal wire in the engine harness probably has an open circuit. Proceed to Step 3.

3. Check The Harness.

   1. Turn the "ECS" switch to the OFF/RESET position.

      Connect a jumper wire from the signal wire to the ground wire. If a ground wire is not near, connect the signal wire to battery ground.

   2. On the Electrical System Schematic, trace the signal wire from the switch to the Main Display Module. The Signal Contact is number 29 at the Main Display Module.

   3. Disconnect the engine harness from the Main Display Module.

   4. At the engine harness connector for the Main Display Module, measure the resistance that is between the Signal Contact 29 and contact 2 (ground).

      Expected Result: The resistance should measure less than 5 ohms.

      Results:

      • OK - The resistance measures less than 5 ohms. The harness resistance is correct. The Main Display Module has a problem. Replace the Main Display Module.

      • Not OK - The resistance is greater than 5 ohms. The engine harness has a problem. There is an open between ground and the signal wire in the engine harness. Repair the engine harness or replace the engine harness.

The Alarm Silence Switch Continually Silences The Alarm

This procedure is for the Alarm Silence switch that continuously silences the Alarm. The "Continually Silences" condition is probably caused by an undesired open circuit. Also, the Main Display Module may cause the problem (unlikely condition).

1. Locate The Switch.

   1. Turn the "ECS" switch to the OFF/RESET position.

   2. Locate the Alarm Silence switch. If necessary, use the Electrical System Schematic to assist in locating the switch.

   3. Check for loose terminal connections or corroded terminal connections to the switch.

   4. Clean corroded terminals and tighten loose connections.

2. Check The Harness.

   1. Disconnect the Signal Wire from the Alarm Silence switch.

   2. Turn the "ECS" switch to the COOLDOWN/STOP position.

      Expected Result: The Alarm should sound.

      Results:

      • OK - The Alarm sounds. The circuit is operating correctly. Check the switch or replace the switch.

      • Not OK - The Alarm does not sound. The engine harness is shorted to ground or the Main Display Module has a problem. Proceed to Step 3.

3. Check The Harness.

   1. Turn the "ECS" switch to the OFF/RESET position.

      Note: The Signal Wire remains disconnected from the switch. Do Not allow the contact to touch any components.

   2. On the Electrical System Schematic, trace the Signal Wire from the switch to the Main Display Module. The Signal Contact at the Main Display Module is number 29.

   3. Disconnect the engine harness from the Main Display Module.

   4. At the engine harness connector for the Main Display Module, measure the resistance between Signal Contact 29 and Contact 2 (ground).

      Expected Result: The resistance should be greater than 5000 ohms.

      Results:

      • OK - The resistance is greater than 5000 ohms. The harness resistance is correct. The Main Display Module has a problem. Replace the Main Display Module. For more information on this subject, see Testing And Adjusting, "Module - Replace".

      • Not OK - The resistance is less than 5000 ohms. The engine harness has a problem. There is a short between ground and the signal wire in the engine harness. Repair the engine harness or replace the engine harness.