Interior light wiring.

Ive removed the interior light on my e plate defender expecting a blown bulb. First of all no bulb present this raised my suspicions!
Ive removed the light (2 nuts) and found no wiring attached but 3 handy plugs? Non of them have any voltage where does the wiring go up to the head lining? All the wiring appears to come from above the driver?
Thank you

Mine goes up the front pillar on the drivers side next to the windscreen running behind the plastic trim