You pulled the fuse out to check 12V+? Double check the fuse - those little ones are tough to tell, sometimes? As others said, check for the 12V+ at the lug end (the part that plugs into the machine. If there's no markings, don't worry - you won't do any damage if you probe the wrong hole. Connect the negative to any good ground (doesn't have to be the plug on the machine). If you have a bracket mount, this is all much easier, of course. As others said, sometimes just unplugging and replugging does it - make sure it's tight, too. A little bit of corrosion inhibitor is never a bad idea.
Do the same checks for the ground pin in the plug - being sure it's solid all the way back to your ground bus. If you verify 12V+ and Ground are good at the plug, then the problem is the machine's plug or the machine, itself.