LAMP AS-HEAD 2502657 - Caterpillar

Illustration 1 g01214691
Schematic for the electrical power supply circuitTest Step 1. Inspect the Electrical Connectors and the Wiring
Turn the keyswitch to the OFF position.
Illustration 2 g01214624
Location of the J1/P1 ECM connectors
Thoroughly inspect the J1/P1 ECM connectors. Inspect all of the connectors that are in the circuit. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Illustration 3 g01214699
P1 connections for the electrical power supply circuit (P1-48) +Battery (P1-52) +Battery (P1-55) +Battery (P1-61) −Battery (P1-63) −Battery (P1-65) −Battery (P1-70) Keyswitch
Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the circuit.
Check the allen head screw for each of the ECM connectors for the proper torque. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness and the wiring for abrasion and for pinch points.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 harness and wiring appear to be OK. Proceed to Test Step 2.
Not OK - There is a problem in the connectors and/or wiring.Repair: Repair the connectors or wiring and/or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are completely coupled. Verify that the repair eliminates the problem.STOPTest Step 2. Check the Battery Voltage at the ECM
Turn the keyswitch to the OFF position.
Disconnect the J1/P1 ECM connector.
Turn the keyswitch to the ON position.
Measure the voltage between P1-48 (unswitched +Battery) and P1-61 (−Battery).
Measure the voltage between P1-52 (unswitched +Battery) and P1-63 (−Battery).
Measure the voltage between P1-55 (unswitched +Battery) and P1-65 (−Battery).
Measure the voltage between P1-70 (keyswitch) and P1-63 (−Battery).
Turn the keyswitch to the OFF position.Expected Result:The measured voltage is between 22 VDC and 27 VDC.Results:
OK - The measured voltage is within the specifications that are given.Repair: The ECM is receiving the correct voltage. There may be an intermittent electrical problem in a harness or in a connector. If an intermittent condition is suspected, refer to Troubleshooting, "Electrical Connectors - Inspect".STOP
Unswitched power out of range - The voltage is not correct for one of the unswitched battery circuits at the ECM. Proceed to Test Step 3.
Keyswitch power out of range - The voltage is not correct for the keyswitch circuit at the ECM. Proceed to Test Step 4.Test Step 3. Check the Batteries
Measure the no-load battery voltage at the battery posts.
Load test the batteries. Use the 4C-4911 Battery Load Tester. Refer to Special Instruction, SEHS9249, "Use of 4C-4911 Battery Load Tester for 6, 8 and 12 Volt Lead Acid Batteries" and Special Instruction, SEHS7633, "Battery Test Procedure".Expected Result:The batteries pass the load test. The measured voltage is the minimum specification for a 24V system.Results:
OK - The batteries pass the load test.Repair: The batteries are OK. There is an open circuit or excessive resistance in the wiring or connections between the batteries and the ECM. Verify that the circuit breaker