Q: What to do if the wire between my sensor and the opener has broke?
A: Sensor wire commonly called bell wire runs from connections on opener to the sensors located at the bottom right and left hand sides of garage door. They are almost always color coded with one wire just white and other wire will have a red, black or some sort of colored markings.
Sensor wires can break apart sometimes because of age. The most common factors that makes the wires break. Some how the staples may have come out and wire can get caught up in the moving parts on the garage door. Also some sensor wires are run up the wall to where the opener attaches to wall and then run thru the opener rail all the way back to opener. When wires are installed thru the opener rail they can sometimes come appart from rail and get caught up in the moving parts of the garage door opener. Anytime wires are not secured properly there is always a chance for wire snapping.
If you notice that a sensor wire looks out of place and hanging down then you need to secure it keeping wire from getting caught up in moving parts. If you see that the wire is snapped in half then you can strip wire insulation and reattach wire connections and making sure to attach wire by color coding and electrical tape to keep wires from touching each other.
Sometimes I have seen a bad wire have a break but was not visible. The wire had separated but the insulation around wire was still in tact so i could not find where the break was. So in that case I had to replace the whole wire.
Bad sensor wires are easy to repair or replace most of the time you should not have to call a technician to solve this problem. But if you have no idea what to do than a technician will be the way to go.