826802T34 Mercury HARNESS/RELAY ASSEMBLY

Illustration 1 g00813712
Schematic
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P1 ECM connectorTest Step 1. Inspect Electrical Connectors and Wiring
Turn the keyswitch to the OFF/RESET position.
Thoroughly inspect the J1/P1 ECM connector and all other connectors in the circuit. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.Expected Result:All connectors, pins, and sockets are completely inserted and coupled. The harness and wiring are free of corrosion, of abrasion, and of pinch points. All connections and grounds are tight and free of corrosion.Results:
OK - The connectors and the wiring appear to be OK. Proceed to Test Step 2.
Not OK - There is a problem with the connectors and/or the wiring.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 2. Check the Resistance through the Solenoid
Disconnect the J508/P508 fan control solenoid connector.
Measure the resistance of the sensor between J508:1 (Fan Control Solenoid) and J508:2 (Solenoid Return).Expected Result:The resistance is between 4.5 and 5.5 Ohms.Results:
OK - The resistance is between 4.5 and 5.5 Ohms. Proceed to Test Step 4.
Not OK - There may be a problem with the fan control solenoid. Proceed to Test Step 3.Test Step 3. Temporarily Install a New Fan Control Solenoid
Remove the fan control solenoid.
Temporarily install a new fan control solenoid.
Connect the Caterpillar Electronic Technician (Cat ET) to the service tool connector.
Turn the keyswitch to the ON position.
Clear any logged diagnostic codes on Cat ET.
Start the engine.
Check for diagnostic codes for the engine fan control solenoid on Cat ET.
Ensure that the engine fan control solenoid is working properly.
Turn the keyswitch to the OFF/RESET position.Expected Result:The engine fan control solenoid is working properly and there are no active diagnostic codes for the engine fan control solenoid.Results:
OK - The fan control solenoid was faulty.Repair: Permanently install the new fan control solenoid.Verify that the repair eliminates the problem.STOP
Not OK - There may be a problem with the harness. Proceed to Test Step 4.Test Step 4. Check for Shorts in the Harness
Disconnect the J1/P1 ECM connector and the J508/P508 fan control solenoid connector.
Measure the resistance between P1:43 (Fan Control Solenoid) and chassis ground.
Measure the resistance between P1:51 (Solenoid Return) and chassis ground.
Measure the resistance between P1:43 (Fan Control Solenoid) and P1:51 (Solenoid Return).Expected Result:The resistance for each measurement is greater than 20,000 Ohms.Results:
OK - The resistance for each measurement is greater than 20,000 Ohms. Proceed to Test Step 5.
Not OK - There is a short between the ECM and the fan control solenoid.Repair: Repair the circuit.STOPTest Step 5. Check for Open Circuits in the Harness
Ensure that the keyswitch is in the OFF/RESET position and that the J1/P1 ECM connector is disconnected.
Use a suitable piece of wire to short P1:43 (Fan Control Solenoid) and P1:51 (Solenoid Return).
Disconnect the J508/P508 fan control solenoid connector.
Measure the resistance between P508:1 (Fan Control Solenoid) and P508:2 (Solenoid Return).Expected Result:The resistance is less than 10 Ohms.Results:
OK - The resistance is less than 10 Ohms. Proceed to Test Step 6.
Not OK - There is an open circuit in the wiring harness between the fan control solenoid and the ECM.Repair: Repair the circuit.Verify that the repair eliminates the problem.STOPTest Step 6. Measure the Current to the Fan Control Solenoid
Reconnect the J1/P1 ECM connector.
The J508/P508 fan control solenoid connector should still be disconnected. Install a jumper wire between J508:2 and P508:2.
Connect an ammeter that is capable of withstanding a 5 amp current between J508:1 and P508:1.
Start the engine and observe the reading on the ammeter that is installed in the circuit.
Turn the keyswitch to the OFF/RESET position.
Remove the ammeter and the jumper wire from the circuit and reconnect the J508/P508 fan control solenoid connector.Expected Result:The ECM is supplying between 0.3 and 1.6 amp to the fan control solenoid.Results:
OK - The ECM appears to be supplying the correct current to the solenoid. Either the pump or the motor may not be responding correctly.Repair: Troubleshoot the hydraulic system. Refer to Testing and Adjusting, "Hydraulic System".STOP
Not OK - The ECM may not be producing a valid supply.Repair: Verify your results.Replace the ECM. Refer to Troubleshooting, "Replacing the ECM" before replacing the ECM.Verify that the repair eliminates the problem.STOP