Boot lock problem - boot won't open - and horn doesn't work

Hi all

My girlfriend is having a few problems with her 2008 Mazda 2 TS2 1.4 diesel 5 door hatchback (in Spirited Green!).

Firstly, the boot won't unlock when you push the button. There is no sound; the locking mechanism isn't engaging. It's not jammed, as you can put the seats down and open the boot manually from inside. So it could be either the solenoid/motor of the boot lock is broke, or the boot unlock button itself is broke. Any idea how I diagnose? Can I unplug the button and hook up 12v to the connections of the boot lock to see if it operates? What do I connect where - don't want to break it if that's not the problem! I once did something with a central locking door solenoid and burnt it out in 2 seconds - it couldn't take a constant signal, it just needed a very quick pulse...

Secondly, the horn isn't sounding. At first we assumed the 2 were related and perhaps a fuse had gone. But my girlfriend says she's checked the horn fuse and it looks fine. But upon googling, I see there is a horn relay... is there a relay AND a fuse? What can we check?

Thanks...

Ross

Are there any magnets on the rear of the car? I put a magnetic antenna for my cell phone booster on my hatch and it would not open until I took the magnet off.