SEAL 9D7987 - Caterpillar

System Operation Description:The possible causes of this failure are listed below:
The battery is discharged or the battery is faulty.
The cables to the starter have failed.
The ignition switch has failed.
The engine is locked.
The starting motor solenoid has failed.
The starting motor has an internal problem.The following tables will be referenced in troubleshooting the starting motor.
Table 1
TYPICAL SYSTEM VOLTAGE DURING CRANKING AT VARIOUS AMBIENT TEMPERATURES    
Temperature     12 Volt System     24 Volt System    
-23 °C (-9.4 °F) to
-7 °C (19.4 °F)     6 to 8 Volts     12 to 16 Volts    
-7 °C (19.4 °F) to
10 °C (50 °F)     7 to 9 Volts     14 to 18 Volts    
10 °C (50 °F) to
27 °C (80 °F)     8 to 10 Volts     16 to 20 Volts    
Table 2
MAXIMUM ACCEPTABLE VOLTAGE DROPS DURING CRANKING    
Circuit     12 Volt System     24 Volt System    
Battery positive post to the positive terminal on the starting motor     0.3 Volts     0.5 Volts    
Battery negative post to the negative terminal on the starting motor     0.7 Volts     1.4 Volts    
Drop across disconnect switch     0.5 Volts     1.0 Volts    
Battery positive post to the positive terminal on the solenoid     0.4 Volts     1.0 Volts    
Battery terminal of the solenoid to the motor terminal of the solenoid     0.4 Volts     0.8 Volts    Test Step 1. CHECK THE BATTERY VOLTAGE
Attempt to crank the engine. Measure the battery voltage with the digital multimeter. Measure the voltage at the battery posts. Do not measure the voltage at the terminal of the battery cable.
Compare the voltage to table 1.Expected Result:The battery voltage is equal to or greater than the voltage in table 1.Results:
OK - Battery voltage is correct. Go to test step 2.
NOT OK - Battery voltage is too low.Repair: Check the charging system. See Special Instruction, REHS0354, "Charging System Troubleshooting". Stop.Test Step 2. TEST THE DISCONNECT SWITCH
Ensure that the disconnect switch is in the CLOSED position.
Measure the resistance across the terminals of the disconnect switch.Expected Result:The resistance should be less than 5 ohms.Results:
OK - The resistance is less than 5 ohms. Proceed to test step 3.
NOT OK - The resistance is greater than 5 ohms.Repair: Replace the battery disconnect switch. Stop.Test Step 3. TEST CABLES FROM THE BATTERY TO THE STARTING MOTOR
Visually inspect the battery cable terminals for the following conditions:
Loose connections
Corroded cablesExpected Result:The cables should be clean and the cables should be tight.Results:
OK - Battery cables are in good condition. Proceed to test step 4.
NOT OK - Battery cables are not in good condition.Repair: Clean the terminals or replace the terminals. Tighten the terminals. Stop.Test Step 4. TEST CABLES FROM THE BATTERY TO THE STARTING MOTOR FOR VOLTAGE DROP
Attempt to crank the engine. Measure the voltage from "Mtr" terminal to ground.Expected Result:The battery voltage is less than the voltage in table 2.Results:
OK - The voltage drop is less than the specified voltage drop. Proceed to test step