* Child safety lock: This is the most common cause. Check for a small switch or lever on the side of the door (usually near the armrest or window controls) that controls the child safety lock. It might be accidentally engaged, preventing the door from being locked from the outside, but allowing it to open from the inside.
* Faulty latch mechanism: The mechanism that locks and unlocks the door might be worn out or broken. This could prevent the door from latching properly even when the door is locked. Inspection of the latch mechanism itself, both inside and out, is needed.
* Broken or disconnected linkage: The linkage that connects the door handle to the latch mechanism might be broken or disconnected. This will prevent the lock from engaging properly.
* Wiring issue (power locks): If your Aerostar has power locks, a wiring problem could prevent the door from locking correctly. This is less likely than the mechanical issues above.
* Door striker plate: The striker plate (the metal piece on the door frame that the latch engages with) might be misaligned or damaged, preventing the door from latching securely.
Troubleshooting Steps:
1. Check the child safety lock: This is the first and easiest thing to check.
2. Inspect the door latch mechanism: Carefully examine the latch mechanism both inside and outside the door. Look for any broken or loose parts. Try to operate the latch manually to see if it's functioning smoothly.
3. Check the door handle and linkage: Operate the inside and outside door handles. Listen for any unusual noises or feel for any looseness in the linkage. Trace the linkage from the handle to the latch mechanism.
4. Test the power locks (if applicable): If you have power locks, try locking and unlocking the doors using the central locking system. Listen for any unusual clicking or buzzing sounds.
5. Inspect the striker plate: Make sure the striker plate on the door frame is properly aligned and undamaged.
If you can't identify and fix the problem yourself, it's best to take your Aerostar to a mechanic or auto repair shop. They have the experience and tools to diagnose and repair the issue.
