On Sat, 26 Jan 2008 09:24:19 -0800 (PST), gary
wrote:

My "L"-shaped hallway has a light switch at the end of each leg, a
switch at the intersection of the legs and a ceiling-light the middle
of each leg.

Originally, the ceiling-lights could be turned on/off from each
switch.

I've replaced the original switches with new switches but now only one
switch operates the ceiling-lights.

Should a three-way switch be installed at each end of the hallway and
the four-way switch be installed at the intersection of the legs? If
the answer is "NO", where should the various switches be installed?

How to I determine what wire gets connected to each terminal of each
switch?

Turn the power off and disconnect all switches.

Turn the power on and use a tester to find the only wire in the bunch
that is hot.

When you find the hot wire, turn the power off and wire the hot wire
to the black screw on the 3-way switch and connect the other two wires
to the other two terminals. (This switch is done)

Turn the power back on and go to the 4-way. One of these wires should
be hot. It will share another wire in the same cable. If you flip
the finished 3-way switch the other wire will become hot. Mark these
two. Turn the power back off and wire these two to the same color
screw terminals on the 4-way switch. Wire the other two wires in the
box to the other two screw terminals of the 4-way switch. (This
switch is done)

Turn the power back on and test the last box. One wire will be hot.
When you flip the switch another wire will go hot. The wire that does
not go hot in either position you will tie it to the black terminal on
the 3-way switch after you turn the power back off. Then wire the
remaining two wires to the other two terminals on the switch. (weekend
project done)

Then, next time, mark the wires or take pictures or do them one at a
time.