Question

73. Technician A says that the battery must be in good condition and at least 75% charged to accurately test an alternator. Technician B says that alternator output should be tested at idle. Which technician is correct?

Answer 1

Technician A is correct. The battery must be in good condition and at least 75% charged to accurately test the alternator

Step-by-step explanation:

The battery is needed to start the vehicle, which, in turn spins the alternator at sufficient speed to keep the battery charged. This means that if your battery is too low, you will be unable to start the vehicle and thus you will also be unable to test the alternator, rendering any additional voltmeter-testing totally useless. If the weather is cold or your battery is old, your battery could be the issue and your alternator might be just fine. That's why you need to check the battery before checking the alternator.