After turning it off.
The other day I believe I saw that GoWesty offers some kind of calibration gizmo for the temp guage.  Maybe someone can chime in or whether it works or not.

Dave B.

-----Original Message-----
From: Rick Cooper <rickdcooper@gmail.com>
To: ddbjorkman <ddbjorkman@verizon.net>
Cc: Vanagon <vanagon@gerry.vanagon.com>
Sent: Wed, Sep 6, 2017 6:23 pm
Subject: Re: Radiator fan switch

Thanks Dave.  I wouldn't be worried except that my needle typically hovers around the 3/4 mark and is at 7/8s of the dial going up that hill.  And I've seen the red light come on a couple of times -- both times I've pulled over asap and it has not come back on after letting it cool a bit.  So I keep thinking there's a problem with the high speed fan.

But maybe it's a wonky gauge.  I'll put the infrared gun in the van and the next time I see the red light come on, I'll take the temp at the rad.

Rick

On Tue, Sep 5, 2017 at 8:06 PM, ddbjorkman@verizon.net <ddbjorkman@verizon.net> wrote:

The Vanagon coolant system, when working correctly, is actually quite robust.  There is an A/C condenser in front of the radiator that VW took into consideration.  As long as you are moving, not stuck in traffic, even at 85+F ambient temp, the low speed fan takes care of things.  As long as your temp guage doesn't get beyond 3/4 and no flashing red light happens, it's working correctly and don't worry about it. To more fully answer your question, your coolant has to reach 85 C/185 F to just turn on the fan.  It takes 95 C/203 F to get the fan to get to high.  That's a lot of degrees.
It's amazing how much one can learn when one has to research a problem.  What's that about VW making owners into mechanics for the past 30 years.

Dave B.

-----Original Message-----
From: Rick Cooper <rickdcooper@GMAIL.COM>
To: vanagon <vanagon@GERRY.VANAGON.COM>
Sent: Tue, Sep 5, 2017 10:14 pm
Subject: Re: Radiator fan switch

I've got the same or at least a similar problem with my radiator fan.

The low-speed fan kicks in as expected but the high-speed fan never kicks
in.  But I know it works since I've done the jumper test at both the switch
and at the high-speed relay.  I have replaced the switch.

Maybe the coolant is not getting hot enough for it to kick in -- I'm in
Victoria, BC where it never really gets super hot, but I would have thought
that going up long hills at highway speed on a hot day (~85 degrees F)
should be enough to trigger the high-speed fan.

At what temp should it kick in?  I've got an infrared temp gun so I could
test that.

Thanks, Rick

On Tue, Sep 5, 2017 at 3:24 PM, Dennis Haynes <d23haynes57@hotmail.com>
wrote:

> Is the radiator getting hot? For testing the wiring there are three wires
> on the fan switch. One is power from the fuse box. That wire jumped to the
> middle will give you slow speed. The two outside wires jumped will give you
> super-fast high speed. If the fan turns on with the AC than most likely the
> fan resistor is good. It is possible you just are not getting the coolant
> hot enough to call for the fan. Infrared temp gun can help here.
>
> Dennis
>
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
> Of David Bjorkman
> Sent: Tuesday, September 5, 2017 1:24 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Radiator fan switch
>
> Hi all;
> Still in SC. replaced the radiator and condenser (after some body work)
> and am having trouble with the fan coming on. Turning on the A/C gets
> starts the fan, so I know it works, but it won't start when the engine gets
> hot.  Fuses check out OK.  How does one check the radiator fan switch.  I
> know that I have to jumper something, but not sure what.  I would really
> like to get this fixed and get back home.
>
> Thanks;
> Dave B.
>