Corvette factory alarm

Hi, I have a customer who has a 1984 Corvette, the car was broken into and the drivers door handle/lock was damaged and has since been replaced. The factory alarm no longer dis-arms when you turn the key in the drivers door but works on the passengers side. Can someone please tell me how the factory system works so I can find the fault?

I haven't worked specifically on an '84 Corvette, but most factory GM alarms work in the same way. --To arm the alarm, you must open a door, hit the power lock switch, and then close the door. (If you lock the doors manually, or using the key from outside the car, the alarm won't arm.) --To disarm it, you must unlock one of the doors using the key, as you already know. There should be a light green wire coming in from each of the front doors---this should see a ground as the key is turned to the unlock position. The key cylinder in each door has a little rotary switch attached to the backside of it, which is what is supplying ground to the green wire. Since the car's doors are fiberglass and not metal, it would make sense that GM would also be running a ground wire into the door, and to the key cylinder switch. So your first step, I think, would be to get the driver's door apart and have a look at the back of the key cylinder. Verify that the switch there is receiving ground, and that it is (or isn't) grounding the light green wire when the key is turned.

Thanks heaps. That should be all I need. Kent