How-to, very simply, trouble shoot the Radiator Fan system on 83.5-91
watercooled (non-diesel) Vanagons.

1. Remove lower grille
2. Unplug the radiator fan temp switch plug on the front of the radiator
3. Make a short jumper wire out of some 10-14 gauge wire
4. Plug the jumper between two of the holes in the plug (there are three)
until the fan comes on. (I forget which holes but you can figure this out
easy).
5.  When the fan comes on, try swapping one end of the wire out into the
other hole until you get the second speed working.
6.  You should be able to have two speeds (low and high and you will be able
to tell the difference as high is like huricane force).
7.  If the two speeds are working then everything in the wiring is good (fan,
relays, wires, plugs etc).
8.  Now run your van up to temperature.
9.  Not far past the center on your coolant temp gauge (to the left of the
LED) the fan should come on low.
10.  If the fan comes on, then you should be OK.  I don't think you can get
the van hot enough to check the higher speed just with the van idling.
11.  If the fan doesn't come on at all or only the high speed comes on at a
higher temperature then your radiator fan sending unit is bad and must be
replaced.

This is just a simple trouble shooting plan for this system but it works well
and will tell you in a very short time exactly what your problem is and how
to fix it.

Hope this helps,
Ken Wilford
http://www.vanagain.com
John 3:16
Phone: (856)-765-1583
Shop:   (856)-327-0027
Fax:     (856)-327-2242