LiftMaster K41-0156-000 Cable tension monitor - Left

The LiftMaster K41-0156-000 Cable Tension Monitor (Left Side) is an OEM safety device designed for LiftMaster commercial door systems that use jackshaft operators. Installed on the left-hand lift cable run at the door’s bottom corner, it continuously monitors cable tension and signals the operator to stop or reverse if slack or a break is detected. As a critical component for compliant installations, this left-side cable tension monitor helps meet UL 325 requirements for sectional and rolling door applications when used with compatible LiftMaster controls.

This replacement part connects to the operator’s dedicated cable tension input as a monitored safety circuit that opens when tension is lost. Proper installation requires mounting on the left side of the door, routing and aligning the lift cable through the sensor assembly per LiftMaster instructions, and completing function tests to verify shutdown and reversal behavior. Use only with LiftMaster commercial jackshaft operators that support a cable tension monitor input; consult your operator’s manual or parts diagram to confirm K41-0156-000 compatibility. Choose the left or right orientation to match the door’s cable routing; the opposite-side version is available separately. For safety and reliability, installation and adjustment should be performed by a qualified door professional, and the system must be tested after setup and during routine service intervals.