Occasionally, you can tell if a cable on your garage door has broken and needs replacement. One key sign is if the garage door suddenly has trouble opening. A door that can't open normally can be caused by several issues, including a failing motor. Therefore, you should check the motor and other parts, such as the springs, to ensure they are not causing problems. If those parts are fine, you may be dealing with a broken spring or lifting cable that needs to be repaired immediately. Wires that are hanging loose can also indicate a problem. If you see frayed wires hanging next to the garage door, it might mean that the lifting cable has snapped. The wires will become frayed before they break, and when they do break, the individual wire strands are frayed even further.