Alternator No-Load Test

NOTE: When performing the following system test, turn OFF all lamps and electrical accessories. Place transaxle in Neutral and apply parking brake.
Battery posts and cable clamps must be clean and tight to ensure accurate meter indications. Before performing any charging system tests, inspect the alternator drive belt for looseness, damage or wear.

Test 1
1. Turn ignition switch to OFF position, then ensure all electrical loads are OFF.
2. Connect Rotunda Digital Volt-Ohmmeter tool No. 105-00051, or equivalent to battery.
3. Read and record battery voltage shown on voltmeter. This reading is called Base Voltage.
4. Start engine, then raise engine speed to 1500 RPM with no electrical loads.
5. Read voltage. The voltage should be in the range of 14.1-14.7 volts. If the voltage increase is less than 2.5 volts, perform Alternator No-Load Test. If there is no voltage increase or the voltage increase is greater than 2.5 volts, repair or replace the alternator assembly.

Test 2
1. Using Rotunda Starting/Charging Tester tool No. 078-00005, or equivalent, connect the positive lead to alternator B terminal wiring harness connector, then negative lead to alternator B terminal.
2. Turn On as many of the vehicle electrical accessories as possible, to force alternator to charge at its maximum voltage.
3. Start engine, then raise engine speed to 2500-3000 RPM.
4. Read and record the maximum alternator amperage output. If amperage output is within 10 percent of rated output, alternator is functioning correctly. If output is below specification, perform Charging System Voltage Output Test. Charging System Voltage Output Test