1. Determine if it's a factory feature: Check your owner's manual. 1997 F-250s *might* have had this as an option, but it wasn't standard on all trims. The manual will tell you if your truck has this feature and if so, if there's a way to disable it (unlikely).
2. Check for aftermarket add-ons: Many aftermarket alarm systems or security systems include auto-locking upon starting. Look for any additional wiring or modules installed under the dash, near the steering column, or in the door panels. These often have a way to configure settings, maybe even a small DIP switch or jumper.
3. Consult a wiring diagram: If you're comfortable working with car wiring (and you should be cautious if not), obtain a wiring diagram for your specific year and model F-250. This will show the circuits related to the door locks and the ignition. It *might* reveal a wire you can disconnect to stop the automatic locking function, but this is risky and could damage your electrical system if done incorrectly.
4. Consult a mechanic or Ford specialist: This is the safest and most recommended approach. A mechanic familiar with 1997 F-250s can diagnose whether the auto-locking is factory or aftermarket and determine the best way to disable it safely without causing further problems.
Important Note: Disabling automatic door locking compromises safety. It's crucial to weigh the inconvenience of the auto-lock against the increased risk of theft or accidental unlocking in a crash. If you're concerned about accidentally locking your keys in, consider carrying a spare key or using a key-less entry system.
