Component Tests and General Diagnostics
COMPONENT TESTSStarter Motor - Motor Feed Circuit
WARNING: Always disconnect the battery ground cable at the battery before disconnecting the starter motor battery terminal lead. If a tool is shorted at the starter motor battery terminal, the tool can quickly heat enough to cause a skin burn. Failure to follow this instruction may result in serious personal injury.
Always connect the 73III Automotive Meter at the component terminal rather than at the wiring end connector. Making a connection at the wiring end connector could result in false readings because the meter will not pick up a high resistance between the wiring connector and the component.
Starter Motor - Motor Feed Circuit
1. Make sure the battery is fully charged; refer to Battery.
2. Disconnect the inertia fuel shutoff (IFS) switch.
3. Connect a remote starter switch between the starter motor solenoid S-terminal and the battery positive (+) terminal.
4. Connect the 73III Automotive Meter positive lead to the battery positive (+) post. Connect the negative lead to the starter motor solenoid M-terminal.
Motor Feed Circuit:
5. Engage the remote starter switch. Read and record the voltage. The voltage reading should be 0.5 volt or less.
6. If the voltage reading is 0.5 volt or less, go to the Starter Motor - Motor Ground Circuit Component Test.
7. If the voltage reading is greater than 0.5 volt, indicating excessive resistance, move the 73III Automotive Meter negative lead to starter motor solenoid B-terminal and repeat the test. If the voltage reading at the B-terminal is lower than 0.5 volt, the concern is either in the connections at the starter motor solenoid or in the starter motor solenoid contacts.
8. Remove the cables from the starter motor solenoid B-, S- and M-terminals. Clean the cables and connections and reinstall the cables to the correct terminals. Repeat Steps 3 through 6. If the voltage drop reading is still greater than 0.5 volt when checked at the M-terminal or less than 0.5 volt when checked at the B-terminal, the concern is in the solenoid contacts. Install a new starter motor.
9. If the voltage reading taken at starter motor solenoid B-terminal is still greater than 0.5 volt after cleaning the cables and connections at the solenoid, the concern is either in the positive (+) battery cable connection or in the positive battery cable itself.
10. By moving the 73III Automotive Meter negative lead toward the battery and checking each mechanical connection point, the excessive voltage drop can be located. When the high reading disappears, the last mechanical point that was checked is the concern. Repair or install a new connection as required.
Starter Motor - Motor Ground Circuit
A slow cranking condition can be caused by resistance in the ground or return portion of the cranking circuit. Check the voltage drop in the ground circuit as follows:
1. Disconnect the IFS switch.
2. Connect a remote starter switch between starter motor solenoid S-terminal and the battery positive (+) terminal.
3. Connect the 73III Automotive Meter positive lead to the starter motor housing (the connection must be clean and free of rust or grease). Connect the negative lead to the negative (-) battery terminal.
4. Engage the remote starter switch and crank the engine. Read and record the steady state voltage reading. The reading should be 0.5 volt or less.
5. If the voltage drop is greater than 0.5 volt, clean the negative (-) battery cable connections at the battery and chassis. Also, clean the engine ground cable connection at the cable mounting bracket. If the voltage drop is still excessive, repair or install a new battery ground cable.