What Does the Bulb Failure (Exterior Light Fault, License Plate Bulb, Brake Light Bulb) Warning Light Mean?

In order to help the driver maintain their vehicle, manufacturers have been using computers and sensors to monitor just about everything in a car. Modern cars are sophisticated enough now to detect when any exterior lights have stopped working. When a bulb goes out, the overall resistance in the circuit changes, which then affects the voltage for that circuit. The computer monitors the circuits for all of the exterior lights for any changes in voltage and then displays a warning light.

What the bulb failure light means

The computer will switch on the bulb failure warning light when it detects any non-normal voltage in any of the bulb circuits. If you see the light come on, check all of the bulbs to find the one that is not working. Be thorough when checking the lights as modern cars have quite a few that can turn on the warning light. Some harder bulbs to find include license plate bulbs, turn signals on the side mirrors, the yellow parking lights at the front of the vehicle, and the tail lights at the back that come on with the headlights.

When you find the bad bulb, replace it and the warning light should turn off. It is possible for false positives to occur in which case the entire circuit would need to be inspected for any damage.

Is it safe to drive with the bulb failure light on?

In most cases, the car is still driveable. Now this doesn’t mean you should ignore the light. The exterior lights are very important for warning surrounding drivers of your car’s position and actions. Having non-functional lights can also make you responsible for damages in the event of a collision.

If you need any help replacing bulbs or if the light won’t turn off, our certified technicians are always available to assist you.


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Ronald

42 years of experience
519 reviews
Ronald
42 years of experience
Hyundai Accent L4-1.6L - Warning Light is on - Tomball, Texas
Ronald was very friendly, knowledgeable, and timely. Way better treatment than the mechanics at the shops in my neck of the for both my vehicle and customer service! He even indulged my son chit-chatting with him as he worked! Thanks again!
Infiniti G35 - Warning Light is on - Tomball, Texas
He was a really good mechanic and fast... He checked for other possible solutions and he was only here for about an 1.5hrs and my car is running like it should.

Brian

24 years of experience
818 reviews
Brian
24 years of experience
Audi TT L4-2.0L Turbo - Warning Light is on - Jacksonville, Florida
On time arrival. Obviously knows autos and clearly explained potential causes of my "idiot" light being on. Could not be more convenient, either.
Nissan Frontier - Warning Light is on - Jacksonville, Florida
Always knows what questions to ask and has never tried to sell me on something that “maybe” might fix the problem. Has always given it to me straight up and gotten two of my trucks up and back on the road in one visit. GREAT Mechanic, always has the right tools for the job and just a cool guy to talk to during a stressful time. Thank you, Brian!

Jeremy

21 years of experience
802 reviews
Jeremy
21 years of experience
Mercedes-Benz C300 V6-3.0L - Warning Light is on - West Palm Beach, Florida
Jeremy is wonderful. YourMechanic sent me Rohon first who messed up my oil change and only put half the required oil in my car triggering lights. Jeremy came out and swiftly corrected the problem. I will only use him going forward.
BMW 320i - Warning Light is on - Lake Worth, Florida
Jeremy was prompt , courteous and knowledgable and went above and beyond to be helpful . Was very happy with the visit .

Rodney

37 years of experience
611 reviews
Rodney
37 years of experience
Jeep Grand Cherokee V6-3.6L - Warning Light is on Inspection - Sacramento, California
Rodney is great to work with, this is the second time he's come out to help me with my vehicle. He showed up early, took care of the issue, then thoroughly explained what was going on. I'll be happy to have him come out any time.
Jaguar XJ8 - Warning Light is on - Sacramento, California
Rodney has worked on my Jaguar before and, as usual, immediately diagnosed the problem and fixed it! Jay B. Hunt

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