Thanks all; now the wiring diagram makes sense. I guess the sun was
getting to me...

This A/C diagram is a horror. So many more things to check. 

On 6/5/05, jimt <camper@tactical-bus.info> wrote:
> On 6/5/05 11:50 AM, "Detroit Bus" <detroit.bus@GMAIL.COM> wrote:
> 
> > Thanks Jim.
> >
> > I've actually never turned on the A/C, since it needs a recharge and
> > I'm not an A/C sort of guy, but I'll go down and give that a shot. Its
> > my understanding that the low speed setting operates independently of
> > A/C, just goes on at a lower coolant temp than high speed.
> >
> > But anyway...the original question still stands:
> >
> > Since I've already jumped the radiator sender switch, and fed 12V
> > directly to the red/black low speed lead which has continuity all the
> > way to the fan motor's positive terminal, and the fan does not
> > respond, what does this mean?  And why is there only one positive
> > terminal when the Bentley implies there should be two?  And why are
> > there no part numbers in the $79 Bentley manual??!!?? sorry just
> > venting there.
> >
> > garrick
> >
> >
> >
> > On 6/5/05, jimt <camper@tactical-bus.info> wrote:
> >> There are two things to check for the low speed.
> >>
> >> If the fan low speed does not operate but high speed does and
> >> If vehicle is air conditioned, turn on the AC.  If the fan comes on the
> >> circuits are good and the sender in the radiator is bad.  It has a two stage
> >> switch in it.
> >>
> >> If the AC fan does not come on then the resistor pack is probably bad.
> >> Found usually behind the headlights on most vehicles.
> >>
> >> If not AC equipped check the resistor pack and the switch in the rad.
> >> jimt
> >>
> >>
> >> On 6/5/05 11:03 AM, "Detroit Bus" <detroit.bus@GMAIL.COM> wrote:
> >>
> >>> Hello from 90 degree NYC:
> >>>
> >>> Why does the Bentley wiring diagram for an 87 show two positive posts
> >>> on the radiator fan motor, when my fan motor has just one positive
> >>> post and one negative post? Both hot leads are combined in one
> >>> connection at the positive post on my motor, 251959455M. My vanagon
> >>> has A/C.
> >>>
> >>> How does the fan motor know whether to go high speed or low speed? My
> >>> low speed option isn't working and i'd like to fix it.
> >>>>> I get 12.1 volts on the lo
> >
> > w speed lead and 12.6 volts on the high
> >>> speed lead  when I jump the radiator thermoswitch (red/black wire and
> >>> red/blue wire, respectively). If the single positive post is correct,
> >>> does this mean I need a new fan motor? Or should the low-speed voltage
> >>> be higher than 12.1? High-speed works fine: the relay clicks and the
> >>> fan spins very nicely.
> >>>
> >>> I've searched the archives and apparently there was something about
> >>> this on Ken Wilford's site at one time which I can't find.
> >>
> >>
> >
> I forgot to mention the relay. Which you located.  From what you say I would
> first replace the relay and then do jumper tests from the two terminals on
> the temp switch.  And I think you need drawing 97.138 and I think you are
> using 97.117  the relay is the one in the center of the three shown.
> 
> Jimt
> 

-- 
Garrick, Queens, NY
'87 GL Weekender

*****
With fond remembrances of:
'77 Beetle 
'67 Bus 
'59 Pickup sn# 460440
'67 Beetle
'76 Camper Bus