was this on the 86 or the 87 ?
what it sounds like to me is the fuse for the breather hose heating element.
It's a separate stand-alone circuit, , like an add-on,  on earlier 2.1
waterboxer vans and is integrated into the wiring on later ones I believe.
  With a stand-alone circuit like that..
I have one on my Digijet EFI 85 vanagon .

I've never seen the need for that heating element in the breather hose
..but I always keep them if there is one there.
scott
www.turbovans.com

On 5/22/2012 10:52 AM, Kurt Grotz wrote:
> I happened to be checking connections in the electrical junction box.   It
> is in upper left corner of engine compartment in vicinity of that wonderful
> slave cylinder.  By the way I cheated and drilled a hole in floor right
> above that slave so to drop a bleeder hose straight down.  No more
> contorting fingers.  Sorry purists.
>
> Anyway I was in that junction box and saw a connection with a fuse.  Fuse
> was blown.   Hmmmm I wondered....is that the cause of one of my minor cost
> of living issues with the ole RexMobile?   At first it looked like it went
> to the upper thermostat housing?   But that was an illusion.  I trailed it
> to the Air Flow unit and that connection that plugs into the top of that
> system.  I am away from vehicle right now so my memory is not perfect.
>   Anyway I replaced the 5 amp fuse and presto.  Not much changed.  It
> started up like normal.   It does seem to be running a little better....but
> it was running fine before.  When I got it running that is.   If you know
> what I mean.
>
> So the long and short is..... what is that fuse for?   What happens when it
> is blown?   I know it still runs.  Could others have missed this in some
> diagnosis or another.   It is out of the way if you didn't know what you
> were looking for.
>
>
>