When to use a fuse or test light?
If an accessory has failed such as brake lights and the fuse tests okay, testing can then proceed further down the circuit such as the brake light switch and so on, a wiring schematic is useful when performing these tests.
How can a blown fuse affect a headlight?
Turn on your DMM and touch the meter probes on each side of the bulb contacts. If there’s continuity, your meter will beep or show zero resistance; otherwise, the display will show infinite resistance, overload, or no sound, depending on your particular meter configuration. The next video shows you how a blown fuse can affect one headlight.
What to look for when checking headlamps and lights?
Checks on wiring and connections must include the spring-loaded contacts, where that type of bayonet bulb holder has been used. A sticking plunger could result in the failure of the lights in that unit, while failure of an insulating washer could mean a short circuit and a dimming of all the lights, or cause a fuse to blow.
Can a battery positive test light be used?
Gently, touch the test light probe to a known power source, we use the battery positive is this example but any known power source such as a fuse or positive battery cable will work.
Turn on your DMM and touch the meter probes on each side of the bulb contacts. If there’s continuity, your meter will beep or show zero resistance; otherwise, the display will show infinite resistance, overload, or no sound, depending on your particular meter configuration. The next video shows you how a blown fuse can affect one headlight.
What should I do if my headlight light is not working?
The best way to do this is to turn the headlight switch on, connect the negative lead on your meter to a known good ground, and touch the positive lead to each headlight connector terminal. One of the terminals should show battery voltage, and the other two should show nothing if the problem is burned out bulbs.
What happens when you turn on the headlights?
When you turn on your headlights, that switch activates a relay. That relay, in turn, actually provides the electrical connection between your headlight bulbs and the battery. Fuses are also involved in order to provide a sacrificial failure point to protect the rest of the wiring.
How to check for voltage drop in a headlamp?
How to Check for Voltage Drop on a Switch, Connector, or Relay in the Headlamp Circuit: 1 Connect your voltmeter across the input and output voltage terminals of the switch, splice or relay. 2 Turn on the circuit. 3 Compare your DMM readings with the values in the table below.