Heater/Blower wiring quickie!

Hi Folks,

Just a quick question regarding my heater blower which stopped blowing.

The blower is fine it's self, I've narrowed it down to the orange/white cable that comes from the blower fuse holder. If I supply that with a constant live from the battery then the blower comes on fine, but otherwise it won't work at all.

Anyone know where that wire originates?

Thanks !