Voltagedrop Tests

Voltage-drop testing can detect excessive resistance in the charging system. These tests determine the voltage drop in the alternator output circuit. Both sides of the circuit should be checked ... insulated side as well as ground side. Excessive voltage drop caused by high resistance in either of these circuits will reduce the available charging current. Under heavy electrical loads, the battery will discharge.

A Sun VAT-40 tester or a separate voltmeter can be used. The following steps outline a typical procedure for performing voltage-drop tests using a voltmeter:

Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

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