Mazda 3 alarm continuously sounding and hazard lights activating on Mazda 3

Some Mazda 3 owners report experiencing issues with their alarm systems, including continuous sounding and activating hazard lights. These problems may arise when unlocking a door with the auxiliary key or door lock switch, causing the horn to sound and lights to flash for about 30 seconds. A common cause is a faulty door actuator, which can short or have wires touching, leading the anti-theft system to mistakenly register the car as unlocked. Additionally, temperature changes, particularly after opening the rear passenger-side door, may trigger nuisance alarms, and avoiding this door can help reduce false alarms. A worn-out door lock actuator in the driver's door can also trigger the alarm and cause interior lights to turn on intermittently, potentially draining the battery. It is advisable for owners to check door actuators for faults, avoid using the rear passenger-side door during temperature fluctuations, and inspect the driver's door lock actuator for wear to prevent further issues.