LEVER & BUSHING AS 5G8484 - Caterpillar

Illustration 9 g00761537
Diode leads
Remove the electrical power from the ECM.
Disconnect the air shutoff relays control wires at the relay.
Remove the diode from the air shutoff relay.
Select the "Diode Check" function on a digital voltmeter.
Refer to Illustration 9. Place the red lead of the digital voltmeter on the diode at location (A). Place the black lead of the digital voltmeter on the diode at location (B).
Measure the voltage drop across the diode.Expected Result:The voltage drop across the diode is less than one volt.Results:
OK - The voltage drop across the diode is less than one volt. The voltage drop across the diode is OK. Proceed to Test Step 7.
Not OK - The voltage drop across the diode is greater than one volt.Repair: The diode is damaged. Replace the diode. Verify that the problem is resolved.STOPTest Step 7. Test the Diode for Current Flow
Reverse the position of the leads for the digital voltmeter.
Measure the voltage drop across the diode.Expected Result:For a diode that is operating properly, the digital voltmeter will indicate an OL across the diode.Results:
OK - The digital voltmeter indicates an OL across the diode for this measurement. The diode is OK. Proceed to Test Step 8.
Not OK - The digital voltmeter does not indicate an OL across the diode.Repair: The diode is damaged. Replace the diode. Verify that the problem is resolved.STOPTest Step 8. Check the Voltage from the Keyswitch to the Voltage Input of the Air Shutoff Relay
Remove the electrical power from the ECM.
Illustration 10 g02577161
Location of the test lamp
Remove the wire at the voltage input of the air shutoff relay.
Connect the test lamp between the wire for the voltage input and the terminal for the voltage input at the air shutoff relay.
Turn the keyswitch to the ON position.
Check the test lamp.
Turn the keyswitch to the OFF position.Expected Result:The test lamp illuminates.Results:
OK - The test lamp illuminated.Repair: The relay contacts are not passing the secondary voltage to the circuit for the air shutoff solenoid. Replace the air shutoff relay. Verify that the problem is resolved.STOP
Not OK - The test lamp did not illuminate. Input voltage is not reaching the relay. Proceed to Test Step 9.Test Step 9. Check the Harness between the Keyswitch and the Air Shutoff Relay
Remove the electrical power from the ECM.
Turn the keyswitch to the OFF position.
Remove the wire from terminal R (keyswitch) of the keyswitch.
Turn the keyswitch to the ON position.
Measure the voltage between terminal B (+Battery) of the keyswitch and engine ground.Refer to Illustration 2 for details.
Measure the voltage between terminal R (keyswitch) of the keyswitch and engine ground.
Turn the keyswitch to the OFF position.Expected Result:Voltage is