HI David, not exactly sure what this means.. I'm not yet convinced that engine temp rather than radiator temp is the desirable control input."

I 'think' that says you are not convinced engine temp sensing would be better.

if you are saying that rad fan triggering should take place on the engine .. I sure agree. That only makes sense. why wait until the radiator sees a hot enough temp anyway ?

perhaps they tried it that way and the rad fan was coming on a lot , or frequently.. and moving the sensing to the radiator prevented that

in an early rabbit, rad fan sensing in on the side of the cylinder head, on the outlet there. - but there, the engine is inches from the rad anyway.

another reason to keep it on the radiator perhaps..- too frequent triggering of rad fan. there are some cars that commonly run the rad fan after shutting down on a warm day . a Renault Le Car does that.. and I always wondered ...what is the cooling affect anyway ...with coolant not circulating ? Perhaps by conduction of the heat through the non-moving coolant, I suppose. That car has it's rad fan sensing on the engine I think. I owned a couple of them ..one just a killer fast small car ...named it Zippy. It was totally happy to have it's speedo needle buried at 87 mph ( 85 mph speedometer ) 1,300 cc's only too I think.

so maybe VW tried it with rad fan triggering on the engine ..and decided not to do it that way., possibly for the two reasons I've suggested.

seems to work well enough the way it is now, to me. Scott www.turbovans.com

----- Original Message ----- From: "David Beierl" <dbeierl@ATTGLOBAL.NET> To: <vanagon@GERRY.VANAGON.COM> Sent: Saturday, July 23, 2011 10:21 AM Subject: Re: Fan resistor

> At 10:44 AM 7/23/2011, Kenneth Lewis wrote: >>One possible alternative. http://tinyurl.com/3mo2qok > > 30 amp (max) controller, 37.5 amp (rated 450W) fan... > > What's the resistance of the fan resistor? It's a two-stage one, > correct? The smaller non-AC fan is a two-speed motor that doesn't > use an external resistor. > > I suspect the unit might be usable if you run its primary output > through a resistor and then parallel the secondary output > direct. That could depend on how it's wired internally, but on the > face of it I think it would work. > > I'm not yet convinced that engine temp rather than radiator temp is > the desirable control input. > > Yours, > David