Right mate this buse boxs are very known as fault I mean they get damaged quite easy and they are expencive to replace for a new one so if you dare you can do what I did, open the box completly so you end up with just a cicuit board and with a soldering iron or gun and a good amount of soldering wire reinforce every little one of the spots that you can reach. Then obout you relay what you can do is replace the relay with something like the r18 pin If the worked for me that could work for you as well.