Car Alarms: Door triger wires, fuse box, start car

Question
I really need help on this! I just installed a car alarm in a 3rd gen eclipse and it has a - and a + door trigger wire on the remote start/car alarm. I found the drivers side door trigger wire in the drivers side fuse box. I wired it to the - from the car alarm and that door works fine. The alarm trips when the door opens. The passengers does not.

Q. How do I wire both the doors with the one wire from the car alarm?

I read a article where it said connect both doors trigger wires and isolate with diodes. I'm a bit lost I know what a diode is but I don't see how it will help if both wires are feeding the 1 wire from the car alarm. Even if one door is opened wont the other still be feeding the car alarm power? Maybe I just don't understand how it works...

Thanks for your help!

Answer
Therein lies the conflict.
Using both (+) & the (-) nulifies what it's
trying to accomplish. Detecting the dome light.

Take off the positive (+) door trigger (FORDS ONLY)
as the manufacturer designed the starter to be fitted to
any given car or truck, and planned for that eventuality.

Cut the (+) trigger and use only the (-) trigger wire
and then to the wire you found if it shows 12 volts when
the doors are closed, and 0 volts when opened.

That will do it.

To get the proper wires for the project,
try www.wirewerx.com

Good luck.

ALARMTEK