In article .com,
wrote:

The foyer in my house has two lights about 1/4 away from each end, and
there are two switches at either end. Something like the following:

Switch A Light 1 Light 2 Switch B

Switches A & B control lights 1 & 2 in the following way:

Switch position Result Comment
A_up, B_up Both lights on == lights 1 & 2 are in parallel
A_down, B_up Both lights off As expected
A_up, B_down Both lights off As expected
A_down, B_down Both lights OFF THIS IS THE PROBLEM

It is the 4th case (A_down, B_Down) that is baffling me. In a regular
3-way switch, the lights should come on. In effect, my 3-way switch
behaves like a "2.5-way switch, so to say". I would greatly appreciate
your advice and suggestions on the following.

Q1. Does this indicate a problem at Switch A? Or Switch B? Both?

Q2. Can this be rectified by opening the switch boxes?

Q3. I have a tester and have done the following electrical work in the
past, without any problems: replace house fuse; replace the outlet box
for the 200 V (dryer); extend the power line and add a motion detector
light to the outside of the garage. Should I attempt to rectify the
3-way switch myself, or should I pay an electrician? (Seems silly to
pay $75, minimum for the visit, to rectify such a simple problem).

Thanks a lot.

Bhoot Nath

Try alt.home.repair.

The switches are wired like this:


A B
/o--------------o\
-----o o----
o--------------o

The bottom connection is broken. I recommend buying two new light
switches because they're cheap ($1 - $5). Probably a wire came loose
from the switch arced away the connector.