The fusible link may have been chosen based on cost alone. There is also one on the high speed radiator fan relay above the fuse box. Even in the low voltage DC world there are many different types-designs of fuses and holders and electrical engineers make decisions for numerous reasons. For the AC there are fuses for each of the fan motors and surprisingly these are on the ground side of those motors. That fusible link appears to be mostly to protect the alternator and the wiring harness from it. Fusible links are often chosen for continuous/motor loads due to their ability to dissipate heat. These are tolerant to be operated closer to their design limit over extended time periods and yet being able to clear the fault current when a short occurs.  

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Larry Alofs
Sent: Wednesday, February 17, 2016 3:52 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: A/C trouble... please help

Dan,
I remember having a problem with the fusible link on the driver's side D pillar.  Corrosion led to heating led to melting...
  I replaced it with a big ole fuse.  Don't remember tho whether it powers the main relay or just the fans.

Just take a quick look at the Bentley and the source of the trouble whould
be obvious.   :-)2

Larry A.

On Tue, Feb 16, 2016 at 3:50 PM, Dan N <dn92610@gmail.com> wrote:

> thanks all for the replies...
>
> it's a tin top so no problem with the cabinet...
>
> I was at the shop this morning but no result yet...
>
> - vacuum and leak test --> no leak
> - charging the system
> - turn ON the A/C and the clutch NOt engaging..
> - there's no power to the compressor
>
> in fact there's NO power to the A/C relay
>
> aargh...
>
> http://s82.photobucket.com/user/26kick/media/IMG_6542.jpg.html
>