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

Indicator Lamp Is Always Flashing

This procedure is for the parameter that has the indicator lamp that flashes all of the time. The "Always Flashing" condition is probably caused by an undesired open circuit. Also, the Main Display Module may cause this problem (unlikely condition).

1. Locate The Switch.

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

   2. Locate the switch that corresponds to the parameter that is always flashing the indicator lamp. If necessary, use the Electrical System Schematic in order 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 switch.

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

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

      Expected Result: The indicator lamp should stop flashing.

      Results:

      • No - The engine harness is open or the Main Display Module has a problem. Proceed to Step 3.

      • Yes - The circuit is operating correctly. The switch has a problem. Check the switch or replace the switch.

3. Check The Harness.

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

   2. On the Electrical Schematic, trace the signal wire from the switch to the Main Display Module.

   3. Determine the signal connector contact number at the Main Display Module.

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

   5. At the engine harness connector for the Main Display Module, measure the resistance that is between the signal contact and contact 2 (ground).

      Note: Jumper wire from Step 2 is still connected.

      Expected Result: The resistance should be less than 5.0 ohms.

      Results:

      • No - The resistance is greater than 5.0 ohms. The engine harness has a problem. Repair the engine harness or replace the engine harness.

      • Yes - The resistance is less than 5.0 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".

Indicator Lamp Never Flashes

This procedure is for the parameter that occurs when the indicator lamp never flashes. The "Never Flashes" condition is probably caused by a short to ground. Also, the Main Display Module may cause this problem (unlikely condition).

1. Locate The Switch.

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

   2. Locate the switch that corresponds to the parameter that never flashes the indicator lamp. If necessary, use the Electrical System Schematic to assist in locating the switch.

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

   4. Clean corroded terminals and tighten the loose connections.

2. Check The Harness.

   1. Disconnect the signal wire from the switch.

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

      Expected Result: The indicator lamp should flash.

      Results:

      • OK - The indicator lamp flashes. The circuit is operating correctly. The switch has a problem. Check the switch or replace the switch.

      • Not OK - The indicator lamp does not flash. The engine harness is open 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 other components.

   2. On the Electrical System Schematic, trace the signal wire from the switch to the Main Display Module.

   3. Determine the signal connector contact number at the Main Display Module.

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

   5. At the engine harness connector for the Main Display Module, measure the resistance that is between signal contact 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 ohm. 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. STOP.