GMC Repair: Blown Fuse!, broken shaft, blown fuse

Question
My Husband's GMC Yucon, I believe it is a 2000, The power steering is not working. I know a few things about cars, and it's my experience that when power steering is going out, it makes a whinning sound.
Here is the deal, my husband hooked up a boat trailer lights, and they didn't work so he worked it around until the work started working. Since then the power steering is no longer working.

My question is.... is it possible that he may have blown a fuse? Would that have anything to do with the power steering? Or should I just expect to replace the pump? There is no leak, there is plenty of fluid.  

Answer
You may have a problem with the magnetic steering assist, but I don't see where it would cause a failure of the power steering system entirely. You could check the pump first for a broken shaft by prying the pulley with a screwdriver. If the shaft is broken it will come out of the front of the pump without much effort and there is the problem. I have seen those shafts break before.