Corolla 1999/2000 Factory Alarm Door Triggers

Good Day, I read the article under 'Car Security and Convenience/Alarm Sensors and Triggers'. I recently purchased a DEI 508d Motion Sensor and attempted connecting it up to the factory alarm system. As you know these DEI sensors come with a 4 pin harness, Red/Black/Blue/Green wires. I connected Red to a constant 12v source, black to a ground bolt, the green is for first stage trigger (I did not connect this up to anything) but instead used the blue wire which is second stage (full trigger) which I tapped into the driver's side door trigger wire (red and white) on my 00 Corolla. When tested, the sensor worked excellent only for a few days then stopped triggering the factory alarm. I did not know what the issue was so I did some investigation, tested the sensor by arming the car and moving around, the RED led comes on as normal with seconds between each trigger. The Yellow led was not coming on at all anymore. Tested the output from the blue trigger wire using a DMM, read at 0.83 volts, according to factory specifications the sensor does send out a negative pulse when triggered. Then I tested my input door trigger wire again, it read roughly 0.2v when the alarm was unarmed (at rest) and about 12.4v when armed, which brings me to article that I read on this site about Door Triggers/Pin Switches where it is stated that some vehicles have trigger wires that change from power to ground and vice versa when car is armed/disarmed. My car just has one red and white wire that leads to the door switch and also controls the DOME light. I then tried to connect the negative trigger wire of the sensor to another door and even the front trunk pin, same results, the motion sensor did not trigger the alarm. I then tried the green wire and instantly it worked great, when tested both the Green and led light came on before the alarm triggered. A few days had passed and the sensor had stopped triggering the alarm again, not sure of what was going on I proceeded to test again, this time the green wire which read around 0.4v each time the motion sensor detected movement. I then tested the door trigger wire again but this time while toggling the DOME light on/off, there was a fluctuation in voltage from 12.4 to around 12.6v when the DOME light was on. I am not sure whether the change in voltage when the DOME light is turned on/off could have blown both zones on the sensor or affected it in a way where it is now malfunctioning. Unfortunately I did not test the output from the blue or green wire BEFORE the problem occurred so I do not know what the original reading would have been or if this new reading is incorrect or has been affected negatively. My questions are: 1) Does these ground readings sound okay or normal for the sensor (to anyone who has maybe worked with these sensors while they were functioning as supposed to ? 2) How would I add a diode/diodes to the blue trigger wire and the red/white door trigger wire to allow the negative pulse from the sensor to flow through and ground the circuit and trigger the alarm also simultaneously blocking the +12v current from potentially entering the sensor and causing damage? Thanks so much, any assistance would be highly-appreciated as I am currently stumped and all progress has been halted by the possible damage to the sensor, I've bought another one which is on the way from Amazon.comjdm