Howdy. Who would you recommend to diagnose an electrical gremlin?

My RS2 keeps blowing the fuse for the brake lights and the CD shuttle does not work.

The latter seems to be the result of a shoddy job removing a cellphone kit just before I took delivery of the vehicle, but it is unclear if the brake lights are related (maybe they wired the shuttle onto that system because the shuttle is in the boot and the electrics were close by).

I'm thinking of getting the shuttle completely disconnected for the moment to see if that helps, but if there is a more scientific way of diagnosing the problem (eg. monitoring current draw at various points), I'd prefer to do that, because sometimes the fuse can last for a few hours and other times for an entire week...

If the fuse blows intermittently, it must be shorting somewhere as the car moves. Try to see if there is any bare wire that might cause a short.