hi guys. i had the problem in my 159 and the guide here with photos, helped me solve the problem without spending a single euro, so i wanna thank the person who did it, and update it since the connecting block in my 159 is very different from that guide, and this may help users with a connecting block like mine. i will be only uploading pics since the text is the same in the other guide so im gonna just quote the user @jamoir. all credits to him. this will also correct the no warning in panel when boot is open.
After reading a few of these threads about the boot light not working I decided to take a further look at mine. I've got a Brera 06. Its boot light wasn't working but the dash 'trunk' warning was. So got the voltmeter out and tested some wires coming out of the boot lock. Looks like one switch was working and the other not as other people have reported. As this unit is closed and not really repairable I decided to hack the wiring. Not sure why it needs two switches anyway. Be better to make one good switch that lasts surely!! Anyway, I took a jumper wire out from the good switch to close the boot light one at the same time. Up-shot... I have a working boot light. Took about 5 mins to do too...
So all I did was:
Remove the plastic cover surrounding the boot lock. Pull it towards you from the back.. it clicks out easily. Careful not to break the little plastic bits though.
Pull down the connecting block on the left (these are the wires coming from the two microswitches inside the lock)
Get a small piece of wire to jump the working switch. Hopefully in the picture you can see which ones I jumped. If not message me. But best thing to do is test it with a voltmeter.
Test that it works (the light instantly comes on when you have the correct one btw). Put your finger in the boot lock bit to open the switch up again, light should go out. Also check that the dash warnings still operate the same. It all does.
Tape close and put all back, test again.
Its pretty hacky but its a lot cheaper than a new lock.
Hopefully this will help a few folk out.