I have a stairwell light that has 2 switches: one downstairs, one upstairs. However, instead of having both switches turn the light on or off, I must turn "ON" the upstairs switch in order for the downstairs switch to work. How do I make it so that either upstairs or downstairs switch will turn the light on and off? Thanks!

 

I have this problem as well with my outside lighting. I have switch in the garage and a switch in the house. The switch in the garage must be on in order for the switch inside to work. It hasn't been a big problem because I never use the switch in the garage to turn on/off the outside lights.

3-way switches are used when two switched control a single light. My guess is that one of the switches is wired wrong but I'm not sure. I'll ask around and if I come up with something I'll post it.

 

3 way switches are tricky. It appears one of the switches are not wired correctly. Here's a website that explains how 3 way switches work.

http://home.howstuffworks.com/three-way2.htm

Whatever you do, make sure to turn off the circuit before you play around with the wiring.

 

Nice graphic. I spoke to someone else down the hall (electrical guy) who has the same problem in his house ((msut be common). The swithc is wired wrong . The hot wire is attached to the wrong side of the switch while the red (or other black) wire is connected where the hot should be. I'm guessing the electricain mixed up the black wires (since one is hot).

So I'm guessing the trouble shooting technique would be too:

a) red wire IS attached to the "hot" side of the switch
swap it with one of the blacks.
If the switch still doesn't work, swap the black wires.

b) red wire IS NOT attached to the "hot" side of the switch
swap the black wires.


REMOVE FUSE OR TURN OFF POWER BEFORE DOING ANY ELECTRICAL WORK!