Coupe GT cooling fan

Huw Powell human747 at
Fri Aug 9 22:40:29 EDT 2002

> The cooling fan in my Coupe GT runs all the time.

All the time as in *all* the time, or just all the time the car is

> I unplugged the connector to the temp sensor at the
> bottom of the radiator and the fan still runs.

so that is not the culprit

> I jumpered the connector pins in pairs (there are 3)
> and the fan did not turn off.  I may not have jumpered
> all 3 together at one time though.

the temp sensor is a normally-open type switch, so you can't turn "off"
the fan by "closing" it anyway.

> I swapped the relay with two others and the fan still runs.

so the relay is also not at fault... meaning, that even in the absence
of a connection to the sensor, voltage and ground are being provided to
the relay to turn it on.  if that is the case there might be a short in
the harness, probably grounding the relay trigger coil, since that seems
to be the way Audi likes to wire these things (12v constant, switched
ground).  Does the fan run with the relay out?

Remember there are two fan circuits, which are mostly electrically
distinct.  Sounds like you have checked out the "running" system to no
avail.  The "after run" system is triggered by a sensor on a bracket at
the back of the cam cover.  try unplugging one of it's wires, and I
believe it also has a relay of its own?

> The a/c switch is turned off. (a/c compressor is seized)

Huw Powell

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