The boot light has never worked on my Yaris so I decided to have a go at fixing it. The switch is inside the door catch and commonly fails apparently.
I took the cover off and although I didn't actually remove the catch, it's not immediately obvious how I can remove the switch from the inside. I can see where the wires enter. I thought I could just clean it or spray WD-40 into it something.
I then closed the boot and realised I must have accidentally displaced something and I couldn't press the button to open it so had to clamber into the back, fold down a seat and release it from the inside.
All working okay now but I'll have a better look in the morning as it had got too dark to see much.
I have had a wonderful idea of why didn't I just buy one of those stick-on LED lamps you can buy in the pound shop and saved myself hassle.