1982 Diesel Vanagon. I had my glow plug relay and glow plug #3
replaced in July because of inconsistent hard starting- it worked
great, until last week.  Now always hard starting and I have to use
the starter to get it warmed and going, but not without a lot of
smoke. The glow plug indicator light on dash still functions
normally.  Fuse? Bad Glow plug? Other? Help, I'm still learning
about diesels.