I will be adding the new ground wire for all gauges this weekend and can take some pictures for you.  I just did the 30 amp main fuse upgrade because it blew and left me in the middle of the lake stranded!  That was very easy and took only 1 hour total.  If you can wait I will post next Monday.
My PSI gauge is eratic, my heat gauge is running high and I want to change that wire before going any further into the problem.
Cheers,
Hungry Man