Try our new info resource - "Aladdin's Cave" (Main menu)Just added a separate link to Ash's Dropbox thread (shortcut)
Check your main battery ground, it looks like you have the same problem as I had with my 74 550.In your pic, see below. It looks like the green earth wire has overheated and melted. This happened in multiple places in my loom. Its caused by a poor battery ground connection, so a lot of current is using the only other path it can, the small green earth wire.The second pic below is my loom, this is what to look out for: