The answer to 'my carbon monoxide detector won't turn on' is that there could be several common causes, including a dead or disconnected battery, a faulty sensor, or an issue with the electrical wiring. Carbon monoxide detectors are essential safety devices, so it's important to troubleshoot and resolve the issue promptly.
First, check the battery. Most carbon monoxide detectors use a 9V battery, which should be replaced annually or when the low-battery indicator light is flashing. If the battery is dead or disconnected, replace it and see if the detector powers on. If the battery is fine, the sensor itself may be malfunctioning and need to be replaced. This is generally a job for a professional electrician, as they can properly diagnose and repair the issue.