Ford Mondeo Mk4 Driver's Door Lock Cylinder Barrel Key Reader 3M5A-R21990-AH

Ford Mondeo Mk4 Driver's Door Lock Cylinder Barrel Key Reader is an original component from the Locks and Latches category, designed for the mechanical operation of locking and unlocking the driver's side door. It is a practical solution for users who want to restore full lock functionality after damage, wear, or an attempted break-in, while maintaining the factory design of the mechanism.

Specifications and technical data

• SKU: 3M5A-R21990-AH
• Mark: Ford
• Condition: Used
• OEM Part Number: 3M5A-R21990-AH
• Substitutable numbers: 3M5A-R21990-AH, 3M5AR21990AH
• Category: Exterior Locks & Lock Hardware

Purpose and function of the lock cylinder

The presented lock cylinder is the component responsible for interacting with the key in the driver's door, providing direct, mechanical control of the latch. In practice, this means the ability to emergency open the vehicle when remote control fails, as well as maintaining full control over the driver's side door locking system.

Thanks to a design consistent with the manufacturer's solutions, the cylinder works with the existing lock mechanism and latch system without the need to interfere with the door structure. This is particularly important for post-accident repairs, after theft attempts, or due to operational wear of mechanical components.

Benefits of using an original lock cylinder

Using an original solution from the Locks and Latches category allows for maintaining the structural integrity of the door and proper cooperation with other mechanism components. In practice, this translates into:

• proper operation of the latch mechanism on the driver's side,
• stable key movement within the cylinder,
• adequate resistance to typical operational loads,
• the ability to restore the factory method of lock operation after repair.

For users who value maintaining the original configuration of the vehicle, such a cylinder is a solution that allows for a technically correct repair without the use of random replacements.

Installation and operational characteristics

The driver's door lock cylinder is designed for installation in the factory opening in the door panel, in the location provided by the manufacturer. The design is adapted to work with the existing lock mechanism and rods, which facilitates integration with other door components.

With proper installation, you achieve:

• consistent operation of the cylinder with the external handle mechanism,
• correct transmission of key movement to the latch,
• the ability to manually open and close the vehicle independently of electronics.

Due to the design consistent with the manufacturer's solutions, the cylinder fits well into the existing door system, without the need for modifications to the panel or load-bearing elements.

Component condition and service application

The offered cylinder comes from disassembly and is a used component, which makes it an attractive option for service repairs when the priority is to maintain reasonable costs while using original solutions. This type of component will work especially well in situations where there has been mechanical damage to the lock, seizure of the cylinder, or interference in the driver's door area.

In practice, the cylinder can be used both for routine repairs and for vehicle restoration after damage, when it is necessary to restore full functionality of the locking mechanism on the driver's side.

Expansion of the Ford lock system

If you are planning a comprehensive repair or upgrade of the door lock area in your Ford and need other elements from the same group, such as latch mechanisms, passenger door locks, or additional cylinders, check the available parts in the Ford Locks and Latches category.

For drivers interested in a broader context of drivetrain operation and the selection of used components, an article describing various four-wheel drive solutions may be helpful – you can find it here: xDrive, 4Matic, quattro or 4Motion – AWD systems comparison.