door trigger wire, 1999 acura integra

For a 1999 Acura Integra, I am looking for the segment of (-) trigger wire just before the dome light.  In my wiring diagram, it is labled light GREEN/ red, and its locatioin is described as above the left kick panel.  I have found this wire in several spots in the kick panel area.  The first one probed is grounded when the door is open, but when I cut the wire the dome light stayed on.  Two others were not grounded with the door switch.  I found one junction harnes way in the back that had three of these wires in it, one grounded with the door switch, one gave some sort of pulse on my multimeter and the other was not grounded and I am not sure if it went only to the dome light.  

I have built a timer circuit to control my dome light (and only the dome light), but it requires a (-) trigger input, which I have already located, and an output wire (-) that goes directly to the dome light ground.  I removed the dome housing and found that the ground wire is in fact the same color scheme (light GREEN/ red), but the wire was obviously a higer gauge than any of those I could find around the kick panel.

Where can I locate the appropriate wire that goes directly to the dome light?  I don't want my circuit to output to to other things like the door open indicator in the instrument cluster etc.  Your input will be greatly appreciated.

Thank You

Andy Huot