Generator Set Control Panel for Switchgear Conversion Caterpillar

LH/RH Switch - Troubleshoot

Usage:

This troubleshooting procedure is for the "LH/RH" switch. The "LH/RH" switch will not toggle the left exhaust temperature and right exhaust temperature. Also, the "LH/RH" switch will not toggle the left air inlet restriction and the right air inlet restriction values on the Display Area. In most cases, the "Doesn't Toggle" condition is caused by one of the following conditions: an undesired open circuit and a problem with the Main Display Module.

Locate The Switch.
1. Turn the "ECS" switch to the OFF/RESET position.
1. Locate the "LH/RH" switch. If necessary, use the Electrical System Schematic to assist in locating the switch.
1. Check for loose terminal connections or corroded terminal connections.
1. Clean corroded terminals and tighten loose connections.

Check The Harness.
1. Disconnect the signal wire from the switch.
1. Turn the "ECS" switch to the COOLDOWN/STOP position.
1. Alternately, ground the signal wire and unground the signal wire.
  Expected Result: The readout should alternate between "LH" values for exhaust temperature and air inlet restriction and "RH" values for exhaust temperature and air inlet restriction.
  Results:
  - OK: The readout alternates between "LH" values for exhaust temperature and air inlet restriction and "RH" values for exhaust temperature and air inlet restriction. The circuit is operating correctly. The switch has a problem. Check the switch or replace the switch.
  - Not OK: The readout does not alternate between "LH" values for exhaust temperature and air inlet restriction and "RH" values for exhaust temperature and air inlet restriction. The engine harness signal wire has probably shorted to ground. Proceed to Step 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 disconnected contact to touch any other objects.
1. On the Electrical System Schematic, trace the signal wire from the switch to the main display module. The signal connector contact number at the main display module is number 19.
1. Disconnect the engine harness from the main display module.
1. At the engine harness connector for the main display module, measure the resistance between the 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 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.