x-900 door switch trigger wire

[piotrpat]

Hello
I have a problem with finding door trigger wire i.e. this which conects (-) from open door switch to interiorl lamp above haed. It should be BLK/RED but where is it? I know that it should be in one of kick pannels but probing wire by wire is not my idea
Best
Piotrek

[grats]

Is it a possibility the light is using a body ground, this means no (-) wire.

[piotrpat]

light has a switch which has two three positions - first (no light), second when the wire from door switch is conected to body, third - when one leg of the bulb is conected directly to ground from the screw holding lamp housing.
Soo there is the wire at least between door switch and the lamp above the head but where to find this.