TANK GP-HYDRAULIC 3291895 - Caterpillar

Before you perform this procedure, determine the proper machine code. The main display module must have the correct part number for the particular machine. If the machine code is not shown correctly, this procedure determines the component that is malfunctioning. This failure could be caused by a failure in the main display module, a wrong harness code plug or a harness that has failed. Note: The harness code and the machine code are similar terms. The codes describe the particular machine. The harness code is the status (open or ground) of the six harness code inputs (connector contacts 3, 6, 12, 16, 22 and 31). The main display module assigns a number to a machine. This number is the machine code. The machine code is shown during harness code mode. Each sales model has a specific harness code. Therefore, each sales model also has a specific machine code. The specific machine code is listed in Systems Operation, "Harness Code Mode". The specific harness code is given in the Electrical System Schematic.Note: The following procedure checks for incorrect harness codes on the inputs for the main display module. Compare the status of the harness code that is found in the test "Determine the machine code" to the status at the inputs for the main display module. The table identifies the connector contacts and wire identification of the harness code circuits. Contacts that are specified as grounded contacts should be checked for opens in the harness. Contacts that are specified as open contacts should be checked for shorts in the harness. Test Step 1. CHECK FOR OPENS
Turn the disconnect switch to the OFF position.
Disconnect the machine harness from the main display module.
Check for continuity between the connector contacts that are grounded contacts and contact 2 (ground). Check for continuity at the machine harness connector for the main display module. Expected Result:The resistance measures 5.0 Ohms or less.Results:
YES - The resistance is 5.0 Ohms or less. The circuit for the harness code is not open. No defect was found in the ground circuits for the harness code. Proceed to test step 2.
NO - The resistance is greater than 5.0 Ohms. The circuit for the harness code is open. Check the harness code plug on so equipped machines. Record the open contact of the machine harness connector.Repair: Repair the open circuits for the harness code that is found or replace the machine harness. If conditions are not resolved, proceed to test step 2. Test Step 2. CHECK FOR SHORTS
The disconnect switch remains in the OFF position. The machine harness to the main display module remains disconnected.
Measure the resistance between the connector contacts that are specified as open contacts and contact 2 (ground). Measure the resistance at the machine harness connector for the main display module. Expected Result:The resistance measures 5000 Ohms or more.Results:
YES - The resistance is 5000 Ohms or more. The circuit for the harness code is not shorted to ground. No defect was found in the circuit for the harness