What component needs to be bypassed during a full field test?

Bypassing the voltage regulator during a full field test is essential because this test is designed to assess the charging system's capabilities under maximum load conditions. The voltage regulator typically modulates the voltage output of the alternator to prevent overcharging the battery and to supply only the necessary power based on the system's demand.

When conducting a full field test, the goal is to measure the maximum output of the alternator without interference from the voltage regulator. Bypassing the regulator allows the alternator to operate at its full potential, which helps in diagnosing whether the alternator itself is functioning correctly and capable of producing adequate voltage and current. If the test reveals that the alternator performs well when the regulator is bypassed, it indicates that the issue may lie with the regulator rather than the alternator.

In contrast, the starter relay, ignition switch, and fuses, while crucial components of the electrical system, are not typically involved in this specific testing procedure. The starter relay is more related to the starting system, the ignition switch controls the power to the ignition system, and fuses are meant to protect the circuits but do not influence the alternator’s output directly during this test.