Aporte original por: joelong43701 ,
I noticed this post is a year old but decided to answer anyway. You probably have either found the problem or used the set to cannibalise to replace bad lights in another set. The problem with the middle set is not the fuse. There is one or more bulbs that probably have a corroded or broken wire. Find the bulb and replace with same color if lights have bulb covers or fix the wire on the bulb. I answered another post that tells how to fix a broken wire.