Window Regulator Ferrule

What is this?

Inside each Model S door is a cable-and-pulley window regulator driven by a DC motor. The motor receives LIN bus commands from the door control module and moves the glass up or down via a spring-loaded tensioner.  Many failures trace to a small plastic bushing used in that tensioning assembly.

The stock regulator uses an under-sized plastic bushing inside a spring-loaded shock that maintains cable tension.  With age, heat, and repeated end-of-travel impacts, this bushing cracks, releasing tension and disabling the regulator.  The photo shows a typical split bushing—once fractured, the cable loses preload and the window stops operating correctly.

• CNC-machined billet — Precision fit; won’t crack, creep, or distort under heat.
• Direct drop-in — Replaces the fragile OE plastic bushing inside the tensioner.
• Restores cable preload — Returns smooth, consistent regulator motion.

Installation requires removing the inner door panel and regulator assembly. Extract the broken bushing (diagonal cutters work well to nibble away remnants), then slide in the billet replacement.
See our – YouTube instructional video.

Tech Support

Questions or installation guidance? Call our hotline: 623-433-8500