LiftMaster K41-0157-000 Cable tension monitor - Right

The LiftMaster K41-0157-000 Cable Tension Monitor, Right Side, is an OEM replacement safety sensor designed for commercial sectional doors driven by jackshaft or hoist-style operators. Often referred to as a slack-cable switch, this right-hand unit monitors the lift cable on the right side of the door and sends a stop signal to the operator if cable tension is lost. By detecting slack or a broken cable, it helps prevent the door from running out of level, derailing, or causing damage to hardware—an essential safeguard for high-lift and vertical-lift sectional door applications in commercial and industrial environments.

This right-side Cable Tension Monitor installs adjacent to the right cable drum/track area and interfaces with the operator’s dedicated cable-tension/slack-cable input as outlined in the operator manual. Proper mounting, alignment, and functional testing are required to ensure the switch trips reliably when tension changes, and adjustments should be performed by a qualified door professional. The K41-0157-000 is intended for use with select LiftMaster commercial operators that support a right-side cable tension monitor; verify compatibility and handedness with your specific model and installation documents. For safety, never bypass the CTM circuit and test the slack-cable function regularly as part of routine door maintenance.