DISC-OUTER 8X7882 - Caterpillar

System Operation Description:Use this procedure under the following situation:Use this procedure to determine if the circuit for the clutch for the A/C compressor is operating correctly. This circuit can be connected to J1/P1-41 input 11 or to J1/P1-62 input 12.Note: Not all vehicle manufacturers, or all trucks for a manufacturer use the Caterpillar cooling fan circuit. Prior to troubleshooting, determine if the vehicle is using the Engine Control Module (ECM) to control the cooling fan circuit. If the cooling fan on the vehicle is not wired to the ECM then the ECM is not being used for fan control.Check the following items in order to determine if a vehicle is using the ECM cooling fan circuit:
The "Fan Control Type" parameter must be programmed to "On/Off" or to one of the options for variable speed. The Caterpillar factory default is "None".
"A/C Fan On Time" is programmed between 1 second and 600 seconds.
A wire is present in the ECM vehicle harness connector J1/P1 (terminal 11) which is output 5 (cooling fan solenoid).
Perform the special test for the "On/Off Cooling Fan". Access each menu in the order that follows: "Diagnostics", "Diagnostic Tests" and "Special Test". Activating and then deactivating the circuit should cause the solenoid to click if the circuit is working properly.The following background information is related to this procedure:Cooling fanThe signal for the cooling fan is provided by the ECM in order to control the cooling fan. An input from one of the following items may cause the fan to turn ON:
Clutch for the A/C compressor
Engine coolant temperature sensor
Air inlet temperature sensor
Exhaust brake
PTO on/off switch
OEM installed A/C high pressure switch
Manual fan override switch
TransmissionNote: If "Fan Control Type" is programmed to "On/Off" or to "Variable Speed Fan Option S" the transmission may cause the fan to turn ON via the J1939 Data Link. The