There are two speeds (I thinks) to that radiator fan. It is actually a two
speed motor. The real early water boxers have some funky stuff including
some weird hoses and you might even have the early Diesel radiator set up.
Do you have a meter? (say yes). At the fan switch connector there should be
three wires. If not you likely have the early set up with two fan switches.
One should have power all the time, one of the ends. Check to chassis ground
to find which one. Connecting that wire to the center will operate the fan
in low speed. That feeds the motor directly. Than if you connect the power
to the other outside wire, it should operate a relay to provide power for
the high speed. Reasons for the fan not to work include blown fuses, melted
fuse holders, bad wires, and yes you can have a bad fan motor.

It is perfectly normal for the temperature gauge to rise somewhat before the
fan turns on. It should normally sit at center or just above the warning
light. There are tolerances in the gauges and thermostats. If you gauge is
working properly and you usually stay below the light you probably have a
defective or incorrect thermostat. Other reasons for the fan not to work
include defective or blocked radiator. Be defective I mean the tanks inside
can crack letting coolant flow in and out without actually traveling through
the core. A past water pump failure (bearings) can damage the case to the
point the water pump does not have sufficient flow at idle/low speeds.  Of
course head and head gasket problems can cause grief.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
jed batchelder
Sent: Thursday, July 28, 2016 4:40 PM
To: vanagon@GERRY.VANAGON.COM
Subject: radiator fan

i have a 1983.5 vanagon with no ac so i dont have a resistor that i can see,
and not sure if the radiator fan is working correctly.  I tested the plug
and when i jump out the one terminal i get the high fan when i do the other
one i get nothing.  is there a low speed to this?  the cooling temp goes
over the center warning light if i am just in idle but not sure how far it
will go before the high fan will kick in

thanks

jed