Make sure the alternator belt deflection and tension are within the specified values.
Disconnect the cable from the negative battery terminal.
Install the ammeter between terminal B and the terminal.
Connect the cable to the negative terminal of the battery.
Turn off all electrical consumers.
Start the engine and set the crankshaft speed to 2000–2500 min⁻¹.
Measure the current at the generator output. Measurements are taken on a "hot" engine at an air temperature of 20°C and a terminal voltage of 13.5 V.
Current strength:
- at 1000 min⁻¹ - 0–75 A;
- at 2000 min⁻¹ - 0–98 A.
Turn on the following power consumers one by one:
- headlights;
- heater fan motor;
- rear window heater.
Check that the current at the B terminal of the alternator increases gradually. If the current does not increase, repair or replace the alternator.