I thought I would post this as a remember a few threads over the last months or so of people struggling with their boots going strange things on their cars.
My car, 08 159 Lusso, has the boot release button badge which I believe is part of the 08 onward revision. Last week as I was driving along my boot decided to open itself whilst I was driving along. I'd stopped to pick up the wife and just as she got in, I went to pull off and I heard the boot release go. Got home and every time I shut it, it popped open again.
I'd said in threads previously that I thought the boot was trying to haunt me as I used to swear it was opening on its own, but I couldn't prove it, until that day.
Upon investigation I found the boot badge release was completed U/S. The slightest touch or tap on the back of the button (inside the boot) would pop the release. I am thinking over time it had gotten some water in it or something and had died, so time to replace.
As you can see the old one was pretty dull, so I wasn't upset to be replacing it.
Open the boot to remove the trunk lid lining by popping the black plastic clips. Just get your hands under the carpet and lift forward, they'll pop out and bounce off your face!
Be sure to remove this screw on the grab handle, but you don't need to pull the plastic piece itself out, just undo the screw:
This reveals the innards of the trunk lid, note the two wiring connectors here. The boot release is the smaller (green/black wires). Disconnect the pop out with screw driver (its clipped in tight!):
Here is the back of the boot badge, get yourself a 10mm (long preferable), with extension socket to remove. As I said, touching any part of this used to set my boot off!
Once removed, don't forget to clean around the hole on the outside before fitting the new one!! I used a dab of t-cut to bring it up nice and clean.
Refitting is simply the reverse of the above. You may find some of the plastic clips break if you're not careful, but replacements can be sought from Halfords for a couple of quid. I had to replace one but I had some in my tool box.
Just put 1 clip in each corner to hold the liner in place, then screw the grab handle back down before you replace the remaining clips.
and call it a nice job well done, only took me 10 mins at most.
May also help to note that the boot badges for the 159 are the same as those fitted to the MiTo, so the badge I have was from ebay and a broken MiTo as it was cheaper than a 159 listed item - fits and works just the same.