The schematic diagram below shows voltmeter hookups for voltage-drop testing of a General Motor-type vehicle cranking circuit. The testing and diagnosing of this circuit may indicate the worn of starter motor, internal high problems, high resistance in starter motor, and the shorted of starter motor.
Accordingly, starter current draw tests can be performed using a voltmeter as shown in above schematic since a voltmeter may tell us the difference in voltage from one test lead to another. A starter current draw tests for 4 cylinder engines needs 150-185 amps, 6 cylinder needs 160-200 amps and 8 cylinder needs 185-250 amps.
Testing GM-Type Cranking Circuit using Voltmeter Hook Up continued »