P3 gauge and light switched power wire

[StuP]

Thanks in advance for any guidance. I've been given a P3 gauge and I'm installing it in the driver side vent. It's all straightforward apart from finding a positive feed for the auto dim feature.

The instructions I've found say to tap into the grey / red wife on the trunk release button, but it's a very thin wire in a very tight space. I doubt I can tap into it without breaking it with my clumsy hands.

Is there another wire that's only live when the lights are on in that top corner of the dash that's easier to access and a bit more robust ?

I cant help but feel one of the wire to the light switch would be a better candidate, but don't want to mess with them at random and find I've picked one that shouldn't be messed with.

[spidertri]

Can't help except to say that I tapped the grey/red trunk release switch wire and it works.