Date:         Wed, 07 Aug 1996 22:22:39 -0400
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         Cetin Seren <cseren@fore.com>
Subject:      Re: Another LED application


I've tried this in a couple other applications.  The circuit itself
is simple.  However, those integral on/off switches with the power "on"
light in the middle look a lot nicer, and since the wiring becomes
simpler they are much easier to install.   I'd say check their prices
out at Radio Shack first.  Make sure they are the type that can take
the current the radiator fan draws (10-15 amps???), unless you're already
using a/the relay for that purpose.

On another note, the overheating with the fan not coming "on" happened to
me last week.  I was thinking that I should install a fan switch, when,
pop-went-the-weasel.....  The hose to the dist unit burst in a cloud of smoke.
After the hose replacement, it hit me: the sensor that activates the
radiator fan is on the wrong side of the water circuit -- if the
thermostat is stuck, the hot water will never get to it, hence it will never
activate the fan.  I also guessed that a stuck thermostat would end up causing
pressure buildup in the hose that burst (the one from under the thermostat
to the dist. unit.).  Sooo, I removed the thermostat (I know, I know, 
it's bad for the engine in cold weather, but I have a few months to find
a decent thermostat until I need to worry about that).  The end result is:
the temp. gauge never goes above 1/2 scale, and no other hose has burst yet.

Sooo, here's the moral of the story:  (IMHO,anyway) if you have the symptom
of temp-indicator-going-all-the-way-up-and-still-no-fan-sound, check
the thermnostat.  You may also be in for the same nasty surprise that
I had.

Cetin


At 10:47 PM 8/7/96 -0500, john wakefield wrote:
>Several of us have installed manual over-ride switches to control our 
>radiator fan circuits when we want them on rather than wait until the 
>radiator switches finally, if ever, kick in.  Some fans have never been 
>heard to automatically come on despite full scale temp meter readings.  I 
>propose that it might be nice to parallel drive each fan circuit with an 
>LED visible from the driver's position.  The high speed fan operation can 
>be heard while driving under 60 mph, but not its low speed operation.  
>This would be interesting information to have while driving. 
>  I posted instructions on how to install a switch for this earlier.  Now 
>I call upon our Zen and the art of LED color selection advisors to tell 
>us what color lamps should be selected for each of these two speeds.
>
>  John Wakefield
>
>
>
>
Cetin Seren				Direct:	412-635-3479
Software Development Engineer         	Main:	412-772-6600
Outbound Technology Group		fax:	412-635-3350
FORE Systems, Inc.			email:  cseren@fore.com	
Research Park, 5800 Corporate Drive	URL:	http://www.fore.com
Pittsburgh, PA 15237-5829