I am happy to report that I have solved the problem. First I signed up for an on-line shop manual that cost me $26.00 per year. I recommend it. But the solution took most of my Saturday (finished about 10PM) Anyway the problem turned out to be the switch in the lift gate latch. There is a DPST micro switch mounted to the latch mechanism. However it requires that the trim, latch and handle be removed from the lift gate, that's where the shop manual came in handy. The problem turned out to be that the switch wasn't making contact with the latch when the lift gate was closed. I isolated the cause (switch contact) by setting the alarm then opening the rear hatch. Nothing happened when I opened it. After examining the switch and latch mechanism I discovered that the switch would never make contact with the latch in it's current position. I removed the switch from the latch mechanism and in doing so broke the mounting pins off of the switch. I thought OH sh*t now I've done it. But it all worked out. In order to repositon the switch I had to modify the mounting bracket that the switch snaps into. I drilled a very small hole in one corner of the bracket and changed the angle of the switch so it actuates the switch when the latch is in the closed position. The switch must have had something missing because it would have never worked the way it was. Now at night I can open my doors or the hatch and my interior lights work. Yea!