I have a circuit I'm trying to wire that's got me somewhat baffled.

I created a crude diagram of what I have.  It's posted on my website:

http://www.iceohio.com/diagram.jpg

Basically the alarm system sends out a pulse down the two wires to lock
it and reverses the polarity to unlock them.  Simple enough.

I want to be able to unlock the Rear Door (RD) actuator independently
of the others with the negative pulse wire (in brown).

The problem that presents itself is that I don't have a constant
circuit to complete with the one wire.  The ONLY way I can see that I
can get it to work would be to use a relay on each wire to the RD
actuator after it splits from the other two.  One for + and one for -
and patch it into the wires going to the RD actuator.

That way, when the trunk latch release buttom is pressed on the remote,
it completes the circuit to both relays, completing a circuit to the RD
actuator in the correct polarity to unlock it.

I'm guessing I'll need diodes (1N4001/L) on the wires coming from the
relays (I'd need one on each, right?).  I can't really use diodes on
the circuit itself, because of the reversing of polarity.  From my
mental tracing, I should be ok there without any more diodes.  Heck, I
may actually not even need the two diodes after the relays, because
when they're not energized, the segment of the circuit should be open,
and electron flow should go as desired.

The ECM is programmable, so I can tweak the length of the pulse to
accommodate any syncronicity issues between the two relays, so I should
be ok there.

It would have been a lot easier if they'd given a two wire programmable
option on the ECM, but I guess it really would have been the same
because they'd just have to use relays in the ECM.

So my question is... Will this work?  I could do it the other way, but
I'd rather leave the relays in a resting state as much as possible.  I
don't know if it really matters, but intuition tells me if you can
accomplish something without electricity, it's the preferred way to do
it :)

Joseph