1. Attempt Extraction with Pliers (Least Invasive, but Risky):
* Try this FIRST: Use needle-nose pliers to gently grip the broken key piece. Wiggle and pull *very carefully*. Sometimes, a small portion might be grasped and pulled free. Be extremely cautious not to apply too much force or you risk breaking the key further or damaging the ignition cylinder.
2. Ignition Cylinder Removal (Most Likely Necessary):
This requires tools and some mechanical aptitude. It's generally recommended to take it to a locksmith or mechanic, but if you're comfortable working on cars:
* You'll need: A steering wheel lock removal tool (if the steering wheel locks), appropriate size sockets and wrenches, and possibly a drill with a small bit. The exact tools depend on the specific Aerostar model, and you'll need to consult a repair manual (Haynes or Chilton are good options) to identify the procedure specific to your year/model.
* General Procedure (This is NOT a precise guide, consult a repair manual): The process usually involves:
* Disconnecting the battery's negative terminal.
* Removing the steering wheel lock (if engaged).
* Removing the ignition switch bezel (the plastic trim around the ignition).
* Removing screws or retaining clips holding the ignition cylinder in place.
* Carefully removing the ignition cylinder itself. There are usually retaining clips or a small retaining screw.
* Once removed: You can usually get the broken key fragment out of the cylinder. *However, you will need a new ignition cylinder and possibly keys*.
3. Professional Help (Recommended):
* Locksmith: A locksmith specializing in automotive locks is your best bet. They have the specialized tools and expertise to extract the key fragment without causing damage. This is generally the most cost-effective and efficient method.
* Mechanic: A mechanic can also remove the ignition cylinder, but they may charge more than a locksmith for this specific task.
Important Considerations:
* Damage Prevention: Avoid using excessive force. The more damage you cause, the more expensive the repair will be.
* Repair Manual: A repair manual specific to your 1991 Ford Aerostar is invaluable. It will provide detailed diagrams and instructions for removing the ignition cylinder.
* Ignition Cylinder Replacement: Once the broken key is removed, you'll almost certainly need a new ignition cylinder and keys. The cost varies but is usually less than the cost of extensive repairs due to DIY attempts gone wrong.
In short: Attempt the pliers method gently. If that fails, a locksmith is your best, safest, and often cheapest option. DIY removal of the ignition cylinder is possible but requires skill, the right tools, and a repair manual; be prepared for the cost of replacement.
