Cooling Fan Output Operation with Fan Control Type Programmed to Three Speed Fan

Conditions to turn Fan OFF for C-15 and C-16 Conditions to turn Fan OFF for C-10 and C-12

Coolant Sensor Temperature < 208°F (98°C) Coolant Sensor Temperature < 198°F (92°C)

The fan has been ON for at least 30 seconds The fan has been ON for at least 30 seconds

Intake Manifold Air Temperature < 151°F (66°C) Intake Manifold Air Temperature < 151°F (66°C)

Engine Retarder ON Strategy is not Active Engine Retarder ON Strategy is not Active

A/C High Pressure Switch not Active A/C High Pressure Switch not Active PTO On/Off Switch in OFF position PTO On/Off Switch in OFF position Manual Fan Override Switch in OFF position Manual Fan Override Switch in OFF position Key Switch turned OFF with Engine Speed Present Key Switch turned OFF with Engine Speed Present

NOTE: The ECM will turn the cooling fan OFF for 10 seconds during an engine shutdown.

17.2 Cooling Fan Output Operation with Fan Control Type Programmed to Three Speed Fan

The Three Speed Fan operates in three modes: brake, slip and direct (full speed). Two solenoids are required for three speed fan control. Refer to “Wiring Diagram 35 -Three Speed Cooling Fan Circuit” on page 78.The fan comes ON in direct mode in the event of an output circuit failure such as an open circuit. This requires relays with normally open contacts (if powering the coil side of a relay), or solenoid valves that deactivate the fan when it receives the disable (high) signal. Additional switching devices in the circuit should cause an open circuit to turn the fan ON. This circuit is designed to withstand a short circuit to “+Battery” voltage and will not be adversely affected if other devices are connected to this line when directly driving a solenoid. When driving relays, connection of other devices to the Cooling Fan Outputs should not be necessary. When the fan is in Brake Mode both output drivers are ON (Fan OFF). In Slip Mode Output #4 driver is OFF and Output #5 driver is ON. During Direct Mode both output drivers are OFF (Fan ON full speed). OEM provided and installed components required: 1) Two solenoids or two relays and two solenoids. Customer Parameter programming required: 1) Cooling Fan Type programmed to Three Speed Fan.

NOTICE Caterpillar requires the OEM to install a warning sticker near the fan indicating the fan is automatically controlled and may come ON at any time.

17.2.1 Direct Mode Operation (Fan ON full speed) will occur under any of the following conditions if engine rpm is less than 2250 rpm:

Direct Mode Operation for C-15 and C-16 Direct Mode Operation for C-10 and C-12

Engine Not Running. Engine Not Running. During Engine Cranking. During Engine Cranking.

Coolant Sensor Temperature increasing > 217°F (103°C). Coolant Sensor Temperature increasing > 203°F (95°C).

NOTE: If the cooling fan is operating in Direct Mode the fan will continue to operate in Direct Mode until coolant sensor temperature is < 207°F (97°C). NOTE: If the cooling fan is operating in Direct Mode the fan will continue to operate in Direct Mode until coolant sensor temperature is < 198°F (92°C).

Active Coolant Temperature Sensor Diagnostic. Active Coolant Temperature Sensor Diagnostic.

Intake Manifold Air Temperature increasing > 178°F (81°C). Intake Manifold Air Temperature increasing > 178°F (81°C).

NOTE: If the cooling fan is operating in Direct Mode the fan will continue to operate in Direct Mode until intake manifold sensor air temperature is < 127°F (53°C).

Intake Manifold Air Temperature increasing > 149°F (65°C) if Boost Pressure > 70 kPa (10 psi).

NOTE: If the cooling fan is operating in Direct Mode the fan will continue to operate in Direct Mode until intake manifold sensor air temperature is < 127°F (53°C).

*Engine Retarder ON in high mode > 3 seconds, when Fan With Engine Retarder in High Mode is programmed to YES.

*PTO On/Off Switch in ON position, when PTO Activates Cooling Fan parameter is programmed to Continuous.

*Manual Fan Override Switch is ON, when the Fan Override Switch parameter is programmed to a selected input. NOTE: If the cooling fan is operating in Direct Mode the fan will continue to operate in Direct Mode until intake manifold sensor air temperature is < 127°F (53°C).

Intake Manifold Air Temperature increasing > 149°F (65°C) if Boost Pressure > 70 kPa (10 psi).

NOTE: If the cooling fan is operating in Direct Mode the fan will continue to operate in Direct Mode until intake manifold sensor air temperature is < 127°F (53°C).

*Engine Retarder ON in high mode > 3 seconds, when Fan With Engine Retarder in High Mode is programmed to YES.

*PTO On/Off Switch in ON position, when PTO Activates Cooling Fan parameter is programmed to Continuous.

*Manual Fan Override Switch is ON, when the Fan Override Switch parameter is programmed to a selected input.

*These items are dependent upon programming of Customer Parameters. The fan will remain on for a minimum of 20 seconds in direct mode following ECM initiated activation and a minimum of 3 seconds in slip speed mode except following engine start up, or if the A/C Pressure Switch Fan On Time is programmed less than 20 seconds. During engine start up, the ECM will keep the fan ON for 2 seconds after the engine has reached the programmed low idle (700 - 750 rpm). This is done because unstable vehicle battery voltage during cranking may cause the fan to cycle