What Causes the Hazard Warning Lights to Keep Flashing?
3 Answers
The hazard warning lights may keep flashing due to issues with the anti-theft chip on the car key, the vehicle's computer system recognizing the anti-theft chip, or some circuits connected to the vehicle's computer. It is recommended to visit a 4S shop to check for electronic faults and try using a spare key to see if the issue persists. Below is an extended explanation: Situations when hazard warning lights should be turned on: When towing a malfunctioning vehicle, both the towing vehicle and the towed vehicle should turn on the hazard warning lights to indicate that the vehicle is in an abnormal state; When visibility is less than 100 meters, turn on the fog lights, low beams, marker lights, front and rear position lights, and hazard warning lights, and keep the speed below 40 km/h while maintaining a distance of at least 50 meters from the vehicle ahead in the same lane; When visibility is less than 50 meters, turn on the fog lights, low beams, marker lights, front and rear position lights, and hazard warning lights, keep the speed below 20 km/h, and exit the highway at the nearest exit as soon as possible.
Last time I drove my old Jeep, the hazard lights kept flashing, which really freaked me out. After checking, I found that the hazard warning switch was stuck in the pressed position, probably because it got accidentally bumped when I parked last time. It could also be that the relay burned out—that little box that controls the circuit—where the contacts stick together and the current won’t stop. A short circuit is another common cause, like when the wiring harness in the trunk gets damaged and water gets in, causing a short. I tried restarting the engine several times before it finally stopped. You really have to be careful about the battery draining too fast. In the end, I went to the repair shop and replaced the switch to fix it. Usually, when parking, remember to close the doors properly and check the switch position to avoid accidentally triggering the alarm. These small issues may seem insignificant, but when you’re in an emergency on the highway and the lights don’t work, it can be life-threatening. Experience tells me that regular checks on switches and wiring connections can save a lot of trouble.
As someone who frequently repairs cars, I've seen all sorts of situations where hazard lights keep flashing non-stop. The main causes are usually a faulty alarm switch where the contacts get stuck and can't cut power, or internal wear in the relay causing it to stick. A blown fuse can also make the lights keep flashing, especially after heavy rain when water shorts the wiring. Once, a customer's car had aging wiring with exposed insulation, causing current leakage that triggered the alarm. During inspection, first use a multimeter to test the switch voltage—if it's high, replace the fuse; if that doesn't work, try unplugging the connector. Don't overlook issues with the body control module either—modern car electronics can glitch and mistakenly activate the hazard lights. In any case, don't delay—flashing lights drain the battery quickly, potentially leaving it dead overnight, and they interfere with normal turn signal use. It's best to take the car straight to a repair shop for diagnosis.
