found a disconnected wire

Anyone familiar with the underside of the drivers facia? reason being ive been sorting out some rather iffy stereo wiring left in my 92 V8. As i was rooting about in the drivers footwell i notice a orange and black wire, with a long pin connector. Its not terminated anywhere.

I had a look on my rave CD and it points me to 3 different wires it could be. 1 is connected to the alarm unit ( Im not sure my disco has standard LR alarm, it has the remains of an aftermarket alarm but i have no remotes for it, although it does have what looks like the LR alarm sounder on the inner wing) The other goes to the ECM, and the other is another wire to the Alarm sounder relay.

Before i start pulling connectors and looking, does anyone know if this wire is suposed to be disconnected, if it turns out it is to do with the alarm(s)? would it be disconnected for a reason, if its the connection to the ECM it will have to wait until my inlet manifold is back on before i can fire it up

lol @ me for bein a numpty!

an orange and brown wire in the rave manual is designated ON not OB as i was searchin fer.

Only wires i can find now relate to Air Con circuit so not too worried