I think you may have been thinking of this post linked below.
The late great Richard Jones of this list did some fan tests, but it
wasn't the city water port fan mod in this case.

http://gerry.vanagon.com/cgi-bin/wa.exe?A2=ind0410A&L=vanagon&P=R15770

RIP, Richard

Mark

Jim. Felder wrote:
> I followed this discussion for a while some years back. If I am not
> mistaken, the effect of the extra fan was insignificant and one person who
> tried it even reported worse fridge performance if I recall. However, there
> may have been much more to the story after the point I dropped th thread,
> so do some research and see what you can find. I think that anything that
> measurably improves the performance of the fridge would be universally
> adopted, and so far nothing has that I know of.
>
> I did install gowesty's replacement for the stock fan. It is robust and
> quieter and moves a lot of air and I think the fridge performance is a bit
> better because of it, especially in very hot weather.
>
>