Symptoms of a Bad or Failing Fog Light Relay

The fog light relay is the electrical relay that is responsible for controlling power to the fog lights. The fog lights are lights underneath the headlights that are designed to improve visibility in dense fog or rain conditions. They are meant to help the driver see the edges of the road when visibility is low. When the fog light relay fails or has any issues, it can cause problems with the operation of the fog lights. Usually a bad or failing relay will produce a few symptoms that can alert the driver of a potential issue.

1. Clicking sound from the relay

One of the first symptoms of a problem with the fog light relay is an audible clicking noise from the relay. Many relays will produce a quiet audible click when they are switched on, however, an excessively loud click may be an indicator that the relay may be having internal issues.

2. Fog lights are always on

Fog lights that remain on at all times are another symptom of a problem with the fog light relay. If the fog light relay shorts internally or has any wiring issues, it can cause the fog lights to remain on at all times. This is obviously an issue, as it will drain the battery of the vehicle as well as significantly shorten the life of the bulbs.

3. Fog lights do not turn on

Another common symptom of a faulty fog light relay are fog lights that do not come on at all. The fog light relay is the switch that controls power to the fog lights, and it is usually controlled either automatically by the computer or manually by the driver. If the relay fails, it will disable the power to the fog lights and render them inoperable.

While fog lights are not typically used in normal driving conditions, they are useful to have in low visibility conditions, such as during heavy rain or dense fog. If you suspect that your fog lights, or relays, may be having an issue, have the vehicle inspected by a professional technician, such as one from YourMechanic, to determine if the car needs a fog light relay replacement.


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Matthew

33 years of experience
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33 years of experience
Pontiac Firebird V8-5.3L - Vehicle Body Electrical and Lighting Inspection - Newport News, Virginia
Arrived on time, very professional and knowledgeable - especially about my old car.
Hyundai Sonata - Brake Pads Replacement (Front) - Newport News, Virginia
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39 years of experience
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Whitney
39 years of experience
Chevrolet Silverado 1500 V6-4.3L - Labor for cap. wire & oil change and parts inspection for high idle - San Francisco, California
I am satisfied with the service I received from Whitney O., he treated me with respect and was patient in explaining his evaluation of my truck. He never onced pressured me about additional work, he came and performed what I requested which was a tune-up and an inspection of the reason my truck was idling high. He notified me of some additional problems my truck was experiencing and explained to me why it was important to repair these issues and the effects it would have on other parts of my engine. I am a woman and my encounters with mechanics in the past have left me feeling fooled and swindled. After Whitney left, I felt relieved to know what service my truck was in need of and have a better understanding of why. I highly recommend him as your mechanic, and he will be my mechanic in the near future.
Chevrolet G30 - Other Inspections - San Jose, California
outstanding, knowledgeable and very polite.

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29 years of experience
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Marco
29 years of experience
Ford F-150 V8-5.4L - Vehicle Body Electrical and Lighting - Highland, California
Great experience! Marco showed up right on time and was very polite and pleasant. He got right to work and assessed my problem quickly and made recommendations for repair which I was able to take care of myself later. Very good experience and would definitely use Marco again!

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6 years of experience
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6 years of experience
Chevrolet Cavalier L4-2.2L - Vehicle Body Electrical and Lighting Inspection - Jonesboro, Georgia
Genuinely seemed to care about meeting the expectation of me (the customer) with a corrective remedy to my automobile's electrical issue. Genuinely seemed to want to deliver long-term issue-free results.

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