Final answer:
To test for voltage presence at headlights, a test light is used, as it lights up when touching a live circuit. Ohmmeters are for resistance, ammeters for current, and a voltmeter would be used for precise voltage measurements.
Step-by-step explanation:
To test for the presence of voltage at the headlights, a technician would use a test light. This tool is designed to indicate the presence of voltage by lighting up when it is in contact with a live circuit. While an ohmmeter measures resistance, an ammeter measures current, and a temp probe is used for measuring temperature, none of these would be the primary choice for testing voltage presence. The correct tool for checking if voltage is present without measuring the exact voltage level is the test light; for precise voltage measurement, however, one would use a voltmeter.