Generator Set Control Panel for Switchgear Conversion Caterpillar

The SCROLL Switch Does Not Scroll

The "SCROLL " switch is used to change Display Area Parameter Values. When the "SCROLL" switch will not change parameter values on the Display Area, use the following procedure. When the "SCROLL " switch does not function properly, the following conditions may be responsible:

• an undesired open circuit

• a problem with the main display module

1. Locate The Switch.

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

   2. Locate the "SCROLL" 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 "SCROLL" switch.

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

   3. Alternately, ground the signal wire and unground the signal wire.

      Expected Result: The readout should scroll from one parameter value to the next parameter value.

      Results:

      • OK: The readout scrolls from one value to the next value. The circuit is operating correctly. The switch has a problem. Check the switch or replace the switch.

      • Not OK: The readout does not scroll from one parameter value to the next parameter value. The signal wire of 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.

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

   3. On the electrical system schematic, trace the signal wire from the switch to the main display module. The main display module's signal connector contact number is "23".

   4. Disconnect the engine harness from the main display module.

   5. At the engine harness connector for the main display module, measure the resistance between the signal contact and Contact 2 (ground).

      Expected Results: The resistance should be less than 5 ohms.

      Results:

      • OK: The resistance is less than 5 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 greater than 5 ohms. The engine harness has a problem. There is an open circuit between ground and the signal wire in the engine harness. Repair the engine harness or replace the engine harness.

The Scroll Switch Continually Scrolls

When the "SCROLL" switch continuously changes parameter values on the Display Area, use the following procedure. In most cases, this condition will be caused by one of the following conditions:

• a short to ground

• a problem with the main display module

1. Locate The Switch.

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

   2. Locate the "SCROLL" 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 "SCROLL" switch.

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

      Expected Result: The Display Area should NOT Scroll from one parameter value to the next parameter value.

      Results:

      • OK: The Display Area does not Scroll from one parameter value to the next parameter value. The circuit is operating correctly. The switch has a problem. Check the switch or replace the switch.

      • Not OK: The readout continues to Scroll from one parameter value to the next parameter value. 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 object.

   2. On the Electrical System Schematic, trace the signal wire from the switch to the main display module. The signal connector contact number is "23".

   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 23 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.