autopage rf 420lcd, 04 mazda 3

The 4 wire port is for sensors that have a warn away chirp built into them (thats what the green wire is for). I dont think you can install that sensor just by plugging it into the port simply because those ports need 4 wires not 3. But you can still install this sensor. Do you have a shock sensor that is plugged into the brain? If so, you can simply tie the radar's trigger wire (blue) into the shock sensors trigger wire. You dont need to use diodes since your alarm cant tell which sensor is which, but you can to be safe. Then you would run the radar's power wire to a constant 12V (using a fuse) and ground the black wire.

How did you connect? Try the green and blue together, also the remote port MAY only work when the alarm is armed.