If the car doors work but the vehicle does not run, what should be checked first?

In situations where the car doors operate but the engine will not start, the safety circuit is crucial to investigate first. The safety circuit incorporates various systems such as the neutral safety switch, which prevents the vehicle from starting unless it is in the proper gear. If the safety circuit is malfunctioning, it could inadvertently prevent the engine from turning over, even if the ignition system and battery are functioning normally. Checking the safety circuit first helps to rule out any simple issues related to safety interlocks that would inhibit engine operation while ensuring critical safety measures are intact.

While the ignition switch, battery, or starter motor can indeed be points of failure, they may not be the immediate concern when the symptoms suggest that the car's electrical components are functioning, as evidenced by the doors working. Therefore, confirming the status of the safety circuit provides a targeted approach to diagnosing why the vehicle won't start, directing attention to a system that directly affects engine operation.