Make sure you remove the negative battery terminal before you start yanking everything. If it's related to your lights, and the interiors are on, you may damage things if there is a fault.
Well to check if a relay is busted you need electrical knowledge (in which I am limited). However, giving it a tap may help or if you pull it out and give it a shake - if it rattles it may be had it.
The only thing I can suggest is the following:
In the boot, check fuse: F4.
In the cabin, check fuses: F7, F11, F23 the relay is R8.
That's about all I can suggest mate, either that or you may have bumped a wire. Really need a diagnostic tool to hopefully find the fault.