Factory Fitted antenna

[SwissXC90]

Compare the above post to this much clearer photo, you should be connecting to Connector A (left hand side of photo) to access the FM1 or FM2 antenna

[SwissXC90]

Originally Posted by Father Ted

I noticed on the connector that there were two connections (and a ground). So I soldered a piece of wire and inserted it into the first slot on the plug. I soldered a second piece, inserted that into slot 3 (2 isn't used), then crossed this over the first and soldered them together. This means that I have both available as receivers. (Pic 1)

You have, by sheer luck, combined the AM and FM1 antennas together !

Which means both AM and FM will work.

If you just want FM, then disconnect the AM antenna (pin 1) and use just the FM antenna (pin 3)

You should also experiment with the FM2 antenna, also on the same connector.

[Father Ted]

Thanks.
I had thought the other connection was ground only, but I see now that the FM2 antenna overlays the ground. Another little project.

[SwissXC90]

The printed tracks are all antennas.
The ground is the metal casing.

If you connect ground to an antenna, it will not work nowhere near as good....

[Father Ted]

SO. I gave up on FM reception. Every alternative I tried gave poor results. I bought a second hand Pure Highway 300 DAB adapter and Windscreen film antenna.
But, as I still had the coax in place, I thought I'd connect to the DAB part of the roof antenna. I removed the antenna amplifier which came with the previous windscreen antenna and soldered onto the DAB connection (didn't have the correct plug). As an afterthought, I also soldered onto the left hand connector which I'd seen was labelled as FM (although was never connected on the Volvo original tuner).
Not only do I get better DAB reception with this set up, I finally have decent FM reception too!
Result!

For anyone else swapping out the head set, here is a photo showing the connections I've used.