Skip the auto shop - Our mechanics make house calls

Symptoms of a Bad or Failing Headlamp Dimmer Switch

headlamp dimmer switch

The headlight dimmer switch is the electrical switch that is used to control the vehicle’s headlight functions. For some vehicles it is a lever that is mounted on the steering column, while on others it may be a button or knob mounted on the dashboard or center console. The dimmer switch is primarily used to switch between the high and low beam headlights, however in many vehicles it also controls the vehicle’s interior lights as well.

As the dimmer switch is used quite frequently, every time the vehicle’s lights are turned on, it can be susceptible to wear over time and eventually need to be replaced. Usually a bad or failing headlight dimmer switch will produce a few symptoms that can alert the driver of a potential issue.

1. Problems switching between high and low beam

One of the first symptoms of an issue with the headlight dimmer switch is problems switching between high and low beams. If the dimmer switch contacts fail or wear out it may cause issues when switching between or turning on the headlights. A bad switch may not work on certain settings, which will leave the vehicle without that particular set of lights. Depending on which lights are affected, this may problems that may render the vehicle unsafe to drive at night.

2. Headlights stuck on one setting

Another symptom of a faulty headlight dimmer switch is headlights that are stuck on one setting. If you notice that the headlights remain stuck on either high or low beam then that may be a potential sign of a bad dimmer switch. A dimmer switch that is stuck on low will leave the vehicle without high beams, while one stuck on high will leave the vehicle without low beams and blind other drivers on the road if the vehicle is driven at night.

3. Headlights do not function

Another symptom, one of a more serious issue, is headlights that do not function. If the dimmer switch breaks it may not be able to turn the headlights on at all. A vehicle without headlights will have very low visibility both on the road and for the driver, and is not safe to drive, especially at night or in the dark. Headlights can also be disabled by a wide variety of other issues, so having the vehicle properly diagnosed is highly recommended.

The headlamp dimmer switch is one of the most important switches on the vehicle, and can cause a compromise in safety for the vehicle when it goes out. If your vehicle is displaying any of the symptoms above, or you suspect that your headlight dimmer switch may be having an issue, have the vehicle diagnosed by a professional technician, such as one from YourMechanic, to determine if the switch should be replaced.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.


Post a question and get free advice from our certified mechanics.


More related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
Insurance Requirements for Car Registration in Kentucky
The Kentucky Transportation Cabinet requires that all drivers in Kentucky carry liability automotive insurance, or “financial responsibility” in order to operate a vehicle legally and maintain vehicle...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...

Related questions

Q: Headlights stay on

Hello. This sounds like the headlight switch is faulty. You might also want to check to make sure you have the headlight switch in either the auto position, or the off position. If the headlight switch is left in the...

Q: Ignition cylinder wobbly

Hi, if the ignition cylinder is able to move around I would suspect the wiring connection inside the steering column. This piece should only rotate and small movements over time can bend wires and cause shorts. I would have the...

Q: After using car wash, lights started flickering - 2001 BMW 325

You can hire a technician to look over the vehicle and remove the splash panels to see if water leaked through and came into contact with the vehicles electronic equipment just to be sure. Have the same technician inspect the...