No power going to garage door starter!? No power going to garage door sensors? We had a self installed craftman...

No power going to garage door sensors?
We had a self installed craftman 1/2 hp garage door opening that worked for 3 years. Then, just this previous week it stopped working...out of the blue. We replaced the sensors. no luck. ended up replacing the entire section, track, all electrical system, everything except the door itself. it still is not working.

There is power going to the part (the light is on) but it is not going to the sensors. We checked to see that within was no impairment to the wiring and here isn't. We tried a different outlet. no luck. tried resetting the fuse box. no luck. there is still no power going to the sensors.

any suggestions???

I looked-for to add that it be always hooked up to a surge protector. When we installed the brand new unit we put within a new surge protector. As I mentioned...here is power going to the unit but none to the sensors (same problem as the dated unit).
How rugged is it to replace a blower...
Answers:    reset breaker on the back of the introduction motor. check wires leading to the sensors, may enjoy a break in the row.
Light will not turn bad?
change the battery