A reference identifying a window-regulator mechanism does not automatically identify a separate replacement motor. That distinction matters when comparing the selected Mazda3 BK rear-left assembly: the mechanism is referenced to BP4K-73-590E, while the supplied package includes a two-pin motor.
Use the complete original assembly and the actual repair requirements to establish the match. Do not treat a mechanism cross-reference as proof that an unconfirmed loose motor will fit it.
Identify the rear-left BK application
The BK rear-left regulator with motor is listed for 01/2004–03/2009 sedan and hatch builds. It is the rear passenger-side selection on an Australian right-hand-drive vehicle, not a front-door assembly.
Record the VIN, BK code, build month and exact door position. A broad Mazda3 title or a motor’s general resemblance does not replace those checks.
Read the complete mechanism photograph
The curved rail, glass carrier, cable route, motor housing and mounting points need to agree with the original. Compare photographs from the same direction so a reversed viewing angle does not obscure the door-hand check.
The orange retainers visible in this view are shipping ties. They should not be counted as electrical leads or used to infer a connector layout. Follow the actual supplied handling instructions and the installer’s procedure; a gallery image is not an instruction to cut or reposition parts.
Decide whether the repair requires a motor or an assembly
The linked replacement is supplied as a regulator assembly with motor. A motor-only offer and a mechanism supplied without a motor are different packages. Check what the workshop has identified as necessary before comparing prices or inclusions.
The two-pin selection also needs to match the original electrical socket and keying. This guide does not establish a pinout, a functional upgrade or interchangeability with another Mazda3 generation.
Use the reference in its proper context
The Mazda catalogue entry for BP4K-73-590E identifies the left window-regulator frame reference. The independent manufacturer’s rear-left assembly entry provides a complete-with-motor comparison. Those descriptions explain why the mechanism identity and the supplied package should be checked separately.
For an enquiry, send the VIN, build month, original reference, door position and accessible connector and mechanism photographs. Mention previous motor or door changes. Have the workshop diagnose the window complaint independently; the reference comparison alone does not establish which component has failed.
Prepared from application records, catalogue checks and the linked product photographs. The featured workshop scene is an AI-generated editorial illustration. Information reviewed on 3 November 2026.