83328M Mariner HOSE

Recommended Actions
Perform the following diagnostic procedures in order:
Check for OEM Vehicle component failure.
Inspect the ECM Vehicle Harness Connector J1/P1. Check for a wire that goes into terminal 28 (Auxiliary Output 4).If a wire is not connected to terminal 28 (Auxiliary Output 4), or Auxiliary Output 4 is not programmed to "Cooling Fan", the ECM is not connected to the Cooling Fan System. The problem is in the OEM Vehicle system.If a wire is connected to the ECM Vehicle Harness Connector J1/P1, proceed to Step 4.b.
Turn the ignition key to the ON position while the engine is OFF.
Connect the Caterpillar Electronic Technician (ET).
Access the parameter for the "Fan Control Type".Ensure that the parameter for the "Fan Control Type" is programmed to On/Off control for an On/Off fan or ensure that the parameter for the "Fan Control Type" is programmed to Three-Speed Fan control for a three-speed fan.If the fan is an On/Off fan, proceed to Step 1.e.If the fan is a three-speed fan, proceed to Step 1.h.
Access the "On/Off Cooling Fan" test.
Ensure that any fan override switches on the dash are in the OFF position.
Listen for the solenoid and/or the relay to click as the test is activated and deactivated.If the solenoid and/or the relay is clicking, the ECM and the circuit to the solenoid and/or the relay are operating correctly.If the solenoid and/or the relay are not clicking, refer to Troubleshooting, "Cooling Fan Circuit and A/C High Pressure Switch Circuit - Test".
Access the "Three-Speed Fan Slip Output" test.
Listen for the Slip Solenoid to click as the test is activated and deactivated.If the Slip Solenoid is clicking, the ECM and the circuit to the Slip Solenoid are operating correctly.If the Slip Solenoid is not clicking, refer to Troubleshooting, "Cooling Fan Circuit and A/C High Pressure Switch Circuit - Test".
Check the "PTO Activates Cooling Fan" parameter.Note: If the problem occurs in PTO mode, continue with this step. If the problem does not occur in PTO mode, skip this step.
Connect ET to the cab data link connector.
Access the configuration parameters on ET.
Check the "PTO Activates Cooling Fan" parameter.
If the parameter is programmed to "Continuous" the cooling fan will run continuously while the engine is in PTO mode.
Check the A/C High Pressure Switch circuit.
Connect ET to the cab data link connector.
Access the status screen for the "A/C Fan Input".If the status screen for the "A/C Fan Input" indicates that the "A/C Fan Input" is Disabled, the ECM is not programmed to use the signal input for the A/C High Pressure Switch. The ECM will not turn the fan ON because of a high A/C Pressure. The problem is in the OEM Vehicle system.If the status screen for the "A/C Fan Input" indicates that the "A/C Fan Input" is OFF, ON or COUNTING, the ECM is programmed to turn the fan ON because the A/C High Pressure Switch circuit is open. If the status screen for the "A/C Fan Input" indicates OFF, ON or COUNTING, proceed to Step 3.c.
Start the engine. Allow the engine to idle. Watch the Electronic Service Tool Status screen that indicates the status of the "A/C Fan Input".If the status screen indicates OFF at any time and the fan is still ON, the A/C High Pressure Switch circuit is operating correctly. The problem is in the OEM Vehicle system.If the status screen indicates ON and/or COUNTING, the ECM is turning the fan ON because the A/C High Pressure Switch circuit is open. Refer to Troubleshooting, "Cooling Fan Circuit and A/C High Pressure Switch Circuit - Test".
Check the Manual Fan Override Switch.
Connect ET to the cab data link connector.
Access the parameter for the "Fan Override Switch".
Access the status screen for the "Fan Override Switch".If the status is ON, either the Manual Fan Override Switch is ON or there is a short in the circuit for the "Fan Override Switch". Refer to Troubleshooting, "Cooling Fan Circuit and A/C High Pressure Switch Circuit - Test".