4000 rad fan

[Cade Carvell]

The Lower temp sensor is  a two wire unit.  When I jumped it nothing
happened.  Does Current flow down here?  I thought it simply checked for
resistance.  The Top radiator hose is hot, I can see coolant going into
the reservoir tank through the upper hose...All hoses get fairly hot..So
assume that the thermostat is fine. When I jumped the connector at the
base of the radiator, nothing happened, but when I turn on the AC I will
get a fan for a 15 seconds..Then it turn off, then back on.  If that
helps at all.

Thanks,


Cade Carvell
National Business Systems, Inc.
2919 West Service Road
Eagan, MN 55121
Office: 651-994-4400

>>> <AUDIJIM at aol.com> 04/25/03 05:54AM >>>
Hello,

I have a 1987 4000cs Q project car. I haven't been under the hood as of
late
(it's sitting under a cover right now) but I can't remember if the rad
fan
temp sensor is a 2 pin or a 3 pin type. Either should have power going
to the
sensor. When you jumped the connector to the sensor, did the fan run?
Did you
check for voltage at the plug? I read you have power just about
everywhere
else. It would seem that your temp sensor is not letting the power go
through
to the fan. Is your thermostat opening? Maybe the temp sensor for the
rad fan
is just fine and the coolant that it sees just isn't hot enough even
though
the cylinder head temp is climbing. If the thermostat isn't opening,
then the
rad sensor doesn't think it need to turn on. I though I would through a
few
ideas at you. This is a very simple circuit that is usually cured with
one or
both of the above.

Jim Furdyn
Audi5TurboTech.com
and
Yahoo e-group:
Audi5zylinderturbotechnik