Avensis T25 hatch, courtesy light in boot

[roystonvasey69]

Hi all, It's a long time since I've been in this forum, probably 8 years or so! But back in the Toyota fold with a 2008 Avensis 2.0d4d TR hatch. Picked it up at the weekend, over the moon with it to be honest. Just one super-picky but super weird fault.

The courtesy light in the boot isn't working. Easy, I thought, blown bulb. No such luck. So tested the bulb holder and switch unit, again perfect. So last resort, tested the feed. And damn me if it's only 6volts! It's the same whether the engine is running, the ignition is on etc. So there's juice there, just not enough. 

Only other thing is the switch I guess, is it in the boot catch on the tailgate? But weird why it's giving 6v with an open circuit!!!