How could a light switch spontaneously change what it does?

We have a light switch in our master bedroom that has always turned on all of the outside floodlights (which is convenient living out in the woods...). Near the front door of the house we have another switch that only turns on the floods on the front side of the house.



After years of this arrangement, the switch in the bedroom seems to have spontaneously changed and now only turns on the floods on the back half of the house!



So I've done a little bit of electrical work (new outlets, additional ones, etc.), but this is beyond my experience. What would cause this sort of thing to happen? The house was built in 1980-81 and is all copper wire.



Thanks!How could a light switch spontaneously change what it does?Are the blubs burned out int he lights that don't come on?



All the other answers are non-applicable until you cancel out the easy stuff.

EricHow could a light switch spontaneously change what it does?A wire connection seems to have come loose, it may be at the switch or farther down the circuit, depending on how it is wired.How could a light switch spontaneously change what it does?One of the switches has gone bad.How could a light switch spontaneously change what it does?Must be down to the other switch i would have thought, as it sounds like the power to the front must go through that switch as well, change the switch that controls the front lights, if that doesnt fix it then its Gremlins, buy a new house ...quick!!How could a light switch spontaneously change what it does?There may be a short in the wires that run from the switch to the lights in the front. The short must have happened when the lights were on, so now the information from the switch is not turning them off.How could a light switch spontaneously change what it does?Sounds like there is probably a loose or free wire to me. You'll need to open up the switch box to find out. There should be a parallel path from the switch that turns on both sets of lights and the switch that just turns on the front lights so when you open it up make sure that both breakers are open. How could a light switch spontaneously change what it does?So I have some questions:

When you turned on the lights from the front door, was it always putting the switch up for on and down for off?

When you turned on the lights from the back door, was it always putting the switch up for on and down for off?

If the answers to these questions are yes then there is no three way switches involved. You do not mention if you have taken apart the switch in the bedroom, is it possible that it is a double pole single throw switch? And the half that is controlling the front lights is defective?

What would happen if you turned on the lights at the front door and then turned on the lights at the bedroom, could you turn out all of the lights from the bedroom, or did you have to go to the front door to turn off the front lights?

Are you the original owners or did you buy from someone else?

What I am assuming is that the back lights were controlled directly by the bedroom switch. I am also assuming that the front lights were controlled by an electronic device containing a relay which could be operated by either the front door switch or the bedroom switch. As someone suggested the wire from the bedroom to the electronic device has become defective. There could be two relays and one of them (controlled by the bedroom switch) is no longer functioning.



Good luck.