According to Patrick Gillette :

P.S. Posts that say "don't switch the switch" or "put tape over the switch"
aren't really helpful. Thanks for playing anyway.

"Don't switch the switch" is actually the _right_ solution here, because you
need to be able to switch the motion detector off in order to reset it
when it goes into "manual mode".

"Manual mode" is where you can use a switch to force the light on
continuously (or off) and ignore the motion detector. Motion detectors
usually go into "manual mode" when they see short duration power glitches,
because it can't tell the difference between a short power failure and
a deliberate enabling of manual mode.

So, if you don't have a switch, and you have a power glitch, the only
way to get it back into "automatic" is to fiddle around with the branch
breaker[*][+]. Nor is there any way to turn it off and keep it off
without killing the branch circuit.

Check the instructions on the motion detector, you'll probably see stuff
like mine says: "turn light switch off for 30+ seconds to restore manual
mode".

You should have figured this (and the wiring rearrangement) all out
before pulling the wiring apart. Unless you've made a diagram of what
was connected to what, and _confirm_ whether it's a three way switching
arrangement on the motion detector circuit, there's nothing we can do. If
you've not made a diagram, and you needed to ask here, you're in a real
jackpot, and you'll need an electrician with test equipment to make
sense out of what you got and need to do.

Heck, does anybody make duplex switches with three way elements? I've
never seen one. Just two two-way switches.
[*] Are any clocks on that circuit? VCRs? ;-)

[+] I have a similar situation. The detached garage flood is a motion
detector, and the only switch for it is in the garage. When we have a
power glitch (or lots of waving branches) in the middle of a raging
snowstorm the flood goes on and stays on. To reset it, either I go out
in the storm in the middle of the night and diddle the switch, or I go
down in the basement to shut off the subpanel feed to the garage.

I'm usually so tired that I either leave it on, or go down in the
basement, shut the subpanel off and leave it off (because chances are if
I just reset it, I'll have to do it _again_), and go back to bed. Then
days later I realize that the garage is dead, and I have to go into the
basement yet _again_ to use anything in the garage. There is no
easy solution for my situation (short of burying new cable. Yuck).

Pain in the butt.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.