0387824 JOHNSON CUP & STOP

Illustration 1 g02309533
Location of the manual purge switch for the cooling fan reversing solenoid
(1) Manual purge switch
Illustration 2 g02340736
Location of the cooling fan reversing solenoid
(2) Control Manifold Gp
(3) Cooling fan reversing solenoid The purpose of a reversing fan is to clean debris from the radiator. By temporarily reversing the direction of the air flow through the radiator fins, debris is purged from the radiator fins. For some applications, the reversing fan is used to heat the engine compartment during cold-weather operation.In the automatic mode, the fan reversing solenoid is controlled by the Electronic Control Module (ECM). The ECM will automatically reverse the direction of the rotation of the fan. The ECM will use a preset time interval to cycle the fan reversing solenoid. The operator can manually reverse the rotation of the fan by pressing the manual purge switch. While the momentary switch is depressed, the direction of the fan rotation will reverse. Once the switch is released by the operator, the fan returns to normal operation and control of the fan will return to the automatic operation.
Illustration 3 g02309293
Schematic for the cooling fan reversing solenoid and manual purge switch
Illustration 4 g02310116
Location of the ECM connectors
(4) J1/P1 ECM connectors
Illustration 5 g02339339
Terminal locations at the J1/P1 ECM connectors
(P1-5) Return
(P1-12) Reversing solenoid
(P1-18) Return
(P1-46) Manual purge switch
Illustration 6 g01250541
Terminal locations at the manual purge switch
(Terminal 2) Return
(Terminal 3) Signal
Illustration 7 g01155187
Terminal locations at the cooling fan reversing solenoid
(Terminal 1) Solenoid signal
(Terminal 2) Return
Table 1
Troubleshooting Test Steps Values Results
1. Inspect the Electrical Connectors and the Wiring
A. Turn the keyswitch to the OFF position.
B. Thoroughly inspect the connectors. Also, thoroughly inspect all of the other connectors in the wiring harness. Refer to Troubleshooting, "Electrical Connectors - Inspect" for additional information.
C. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector and the sensor connectors that are associated with the active diagnostic code.
D. Check the harness for abrasions and pinch points.
Electrical Connectors and Wiring
Result: The harness and wiring are OK.
Proceed to Test Step 2.
Result: There is a problem with the harness and/or wiring.
Repair:Repair or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are coupled.
If the problem is not resolved, proceed to Test Step 2.
2. Check the Resistance of the Solenoid Coil
A. Turn the keyswitch to the OFF position.
B. Disconnect the reversing solenoid for the variable pitch fan.
C. Measure the resistance between 1 (solenoid) and 2 (Return).
The correct resistance of the solenoid coil at 25° C (77° F) is 32 1.6 Ohms.
32 1.6 Ohms
Result: The resistance of the coil is within specifications. The coil is OK.
Proceed to Test Step 3.
Result: The resistance is not within specifications.
Repair: There is a problem with the coil. Install a new cooling fan reversing solenoid.
If the problem is not resolved, proceed to Test Step 3.
3. Use Cat® Electronic Technician (ET) to Check the Status of the Manual Purge Switch
A. Connect Cat ET to the service tool connector.
B. Turn the keyswitch to the ON position.
C. Observe the status for Engine Fan Reverse Switch Position on Cat ET while you operate the switch.
D. Turn the keyswitch to the OFF position.
Status of the Switch
Result: The status shows the expected result. The manual purge switch is working properly.
Proceed to Test Step 5.
Result: The status does not show the expected result. The ECM does not recognize the input from the manual purge switch.
Proceed to Test Step 4.
If the problem is not resolved, proceed to Test Step 4.
4. Check the Manual Purge Switch
A. Turn the keyswitch to the OFF position.
B. Disconnect the connector for the manual purge switch.
C. Measure the continuity between P1-46 (manual purge switch) and P1-5 (return) with the manual purge switch in the released position.
D. Measure the continuity between P1-46 (manual purge switch) and P1-5 (return) with the manual purge switch in the depressed position.
Continuity
Result: There is no continuity when the switch is in the released position. There is continuity when the switch is in the depressed position.
Proceed to Test Step 5.
Results: The continuity of the circuit is not acceptable. There is a problem with the manual purge switch.
Repair: Replace the manual purge switch with a new switch.
If the problem is not resolved, proceed to Test Step 5.
5. Check for a Short in the Harness for the Cooling Fan Reversing Solenoid
A. Disconnect the J1/P1 ECM connector.
B. Measure the resistance between P1-46 (manual purge switch) and chassis ground.
C. Measure the resistance between P1-12 (reversing solenoid) and chassis ground.
D. Measure the resistance between P1-46 (manual purge switch) and P1-5 (return).
E