Is there already one in the standard ISO block on the car?

I'm going to be wiring in an amp today or tomorrow, so I need to know, as it is not clearly marked.

This is the diagram on my Head Unit, if that helps.





Thanks

Well, I've answered my own question with the help for Mr multimeter.

It's the one marked with an Aerial symbol. I imagine this is no surprise to those in the know, but thought I would add the information here.

By the way, on the car side of the ISO connector for this "aerial" wire is a red/brown cable, but the aerial booster in the nearside C-Pillar has a green/brown wire, and a plain brown one in it.