Date:         Fri, 15 Jul 94 11:22:48 PDT
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         David.Kao@eng.sun.com (David Kao)
Subject:      Re:Vanagon Temp Guage II

Joel, did you say if I am starting that temp gauge subject again? You bet.
But I promise this temp gauge II is worth your reading joy. Maybe it is for
your weekend hard work too.

About 2 weeks after I bought my 84 GL and after a trip I made to San Francisco,
where a brand new bumper had its first dent made, I decided that I got to build
a switch on the dash so that I can turn on the radiator fan myself. I did not
trust the thermoswitch that VW had on my van. On my trip to the city the gauge
looked kinda crazy and the fan never came on. I worried.

So I bought the bently manual and studied the schematics and within a few days
I had the switch installed. Since then whenever I want to scar a cat or dog
or sometimes a human being in front of my van, or if the temp gauge is about to
go crazy I flip on the switch.

If you already had such a switch hit delete now. If not, but you are bored, hit
delete now too. Otherwise read on.

Behind the fuse box (you do know where it is, don't you?), there are relays.
one of them is a relay for the radiator fan. According to the schematics, there
is a thermoswitch which will turn on the fan when it determines that it is hot.
This relay is actually a secondary circuit. It is controlled by another 
thermoswitch. When this secondary switch determines that it is way too hot it
turns on the relay. The relay then turns on the fan.

The primary circuit does not use a relay. The circuit also has a current
limiting resister so that the fan doesn't try to cool the radiator too hard.
However, the secondary circuit does not have such resistor. The fan will 
blow very hard and make a very loud howling. It does cool faster when the 
engine is crying bloody murder though.

What I did was add a switch which connects, when flip to on, the two terminals
which are supposed to be connected when the relay is turned on. The terminal
numbers are 30 and 87. Just solder 2 wires (speaker wire is fine) to these
terminals and solder the other ends to a switch. The wires should be soldered
to the socket of the relay, not the feet of the relay. Use thicker gauge wire
if possible.

If you don't like the howling noise of the fan, you may add a 1/2 to 1 ohm
20 watt resister to the wire to limit the current through this bypass switch.
Still bored? should have hit delete earlier. if not, read on.

The reason this switch is important is that I don't trust the thermoswitch on
the primary circuit. It is likely the contact will burn out and the fan will
never come on. Although the 2ndary circuit will kick in there is a chance
that the engine is in pain. With the switch I can turn the fan on whenever
I notice that the temp gauge is about carzy. Beware Vanagon engines are 
pretty much dead on very first overheating.

OK, it's friday. Hope this thread will make you guys sweat for good for your
vanagon during the weemend. Ha ha .....

David