Skip the auto shop - Our mechanics make house calls

How Does the Hazard Switch Work?

Hazard Switch

When you experience difficulties while driving like a flat tire, running out of gas, or an unfortunate accident, your vehicle can be immobile at the side of the road or worse, in an active lane of traffic. If this happens to you, turn on your hazard lights. The hazard lights on your car indicate to other drivers around you that you are in trouble or are having problems with your vehicle. They tell other motorists to avoid getting too close, and are a signal for help if the hazard lights are combined with an open hood.

How do the hazard lights work?

Your hazard lights are operated by pressing the hazard switch on your dashboard. On some vehicles, there is a button on the top of the steering column shroud, while on older vehicles they may turn on when a hazard switch under the column is pulled down. The hazard switch will activate the hazard lights on your vehicle anytime there is battery power. If your car stalls because you ran out of gas, have mechanical problems, or a flat tire, the hazard lights will work whether your car is running, the key is in the ignition or not.

The only time the hazard lights will not operate is if the battery is completely dead.

The hazard switch is a low-current on/off switch. When activated, it completes a circuit. When it is deactivated, the circuit is opened and power no longer flows.

If you’ve pressed the hazard switch:

  1. Power is routed through the hazard light relay to the signal light circuit. Hazard lights use the same wiring and lights as the signal lights. The low-current hazard switch enables the relay to send current through the lighting circuit to the flasher.

  2. The flasher relay pulses the lights. When power runs through the signal light circuit it goes through a module or flasher that only emits a pulse of power rhythmically. The flasher is the part that makes the lights flash on and off.

  3. The signal lights flash continuously until turned off. The hazard lights will continue to flash until the hazard switch is turned off or there is no longer power flowing, meaning the battery dies.

If your hazard lights don’t function when the button is pressed or they turn on but don’t flash when engaged, have a professional mechanic inspect and repair your hazard warning system immediately. It is a safety system and must operate at all times.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

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

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.

GET A QUOTE

More related articles

How to Find the Keyless Code on a Ford Explorer or Mercury Mountaineer
Many Ford Explorers and Mercury Mountaineers were manufactured with an option known as the Ford keyless entry keypad. Some models refer to it as SecuriCode as well. It...
Veteran and Military Driver Laws and Benefits in New Mexico
The state of New Mexico offers a number of benefits and perks for those Americans who have either served in an Armed Forces branch...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...


Related questions

Q: Car headlights randomly turning on and flashing while car is off.

Hi there. Check all of the vehicle grounds to the lighting circuits and the ignition circuits. Make sure that the grounds are cleaned and tightened. A loose ground will cause circuits to malfunction and not work correctly. If you need...

Q: Popping sound when braking and turning.

It's difficult to say for sure without hearing the noise firsthand, but it sounds like you may have a bad CV axle. The CV axle transmits power from the transmission to the wheels, while following the up and down motions...

Q: How do you use the hazard lights?

Like all other vehicles on the road, your SUV is equipped with emergency hazard lights. These should be activated anytime you’re stranded on the side of the road to provide visibility for oncoming traffic and to enhance safety. Depending on...