INSULATOR 7N7797 - Caterpillar

Note: The 163-0096 Diagnostic and Calibration Tool can be used in order to troubleshoot this component. Refer to the "Owner's Manual" for more information.The following procedure should be used in order to troubleshoot the thermocouple module.
Determine the number of thermocouples that have a problem.The results of the preceding procedure are in the following list:
The problem appears in the first four thermocouples in a module or the last four thermocouples in a module. Proceed to test step 4.
The problem is a single reading for the thermocouples or all of the thermocouples in a single module. Proceed to test step 5.
Bodily contact with electrical potential can cause bodily injury or death.To avoid the possibility of injury or death, ensure that the main power supply has been disconnected before performing any maintenance or removing any modules.
To avoid potential damage to the processor, handle all modules by the ends of the carrier or edges of the plastic housing. Skin oil or dirt can corrode metallic surfaces, inhibiting electrical contact.
Disconnect the power supply.
Check the electrical connectors and check the wiring for damage or bad connections.
Check the cold junction compensator.
Disconnect the power supply.
Exchange the cold junction compensator on the module.
Connect the power supply.The results of the preceding procedure are in the following list:
The problem follows the cold junction compensator. Test the cold junction compensator. Refer to test step 7.
The problem stays with the 4 thermocouples. Proceed to test step 5.
Test the thermocouples.
Disconnect the power supply.
Perform a test on the thermocouples. Refer to Troubleshooting, "Thermocouple Sensor".The results of the preceding procedure are in the following list:
The thermocouples are not functioning properly. Replace the thermocouples that are not functioning properly.
The thermocouples are functioning properly. Test the thermocouple module. Proceed to test step 6.
Check the module.
Disconnect the power supply.
Remove the module from the base.ReferenceTesting and Adjusting, "Input Module and Output Module - Replace".
Disconnect the power supply from a known good base.
Install the module into the known good base.
Connect the power supply to the known good base.The results of the preceding procedure are in the following list:
The module is functioning normally. Check the pins in the terminal base. Repair any damaged pins.
The module is not functioning normally. Replace the module. Refer to Testing and Adjusting, "Input Module and Output Module - Replace".
Test the cold junction compensator.
Locate the three pins on the side of the cold junction compensator.
Measure the resistance between the two outside pins.The results of the preceding procedure are in the following list:
The resistance is greater than 10,000 ohms when the temperature is 21 °C (70 °F). The cold junction compensator is functioning properly. Proceed to test step 5.
The resistance is NOT greater than 10,000 ohms when the temperature is 21 °C (70 °F). The cold junction compensator is NOT functioning properly. Replace the cold junction compensator.Note: The resistance of the cold junction compensator changes with temperature.