Some cars may differ, but most headlights have fuses for each individual headlamp. If your headlights are functional on the low-beam setting, but won’t switch to high beams, the first thing a mechanic will check is the fuse.
The second thing to check is the headlamp bulb. The mechanic can replace a high beam with a new bulb. If that doesn’t work, it’s most likely that the relay that switches the system to high-beam supply has failed.
If it isn’t bulb trouble or relay failure, the problem may reside in the light switch itself. To check that component, a multimeter and a wire-piercing probe are essential aids, and the mechanic will refer to your car’s wiring diagram. For steering column-mounted light switches, where wiring for the car’s airbag is also routed through the column, it may be necessary to remove the steering wheel to replace the switch.
Common reasons for this to happen:
- Bulbs are burnt out
- Dimmer switch is bad
What to expect:
A top-rated mobile mechanic will come to your home or office to determine the source and cause of the headlight issue, and will then provide a detailed inspection report that includes the scope and cost of the necessary repairs.
How it's done:
To diagnose this issue, the mechanic will confirm that the headlight switch is receiving power from the battery, and then confirm output voltages to both low- and high-beam circuits.
How important is this service?
Headlights are a critical safety feature of any car. Book a mechanic to perform a thorough inspection as soon as possible.