[urq] UrQ After run Radiator Fan

[Tony Lum]

At 06:22 PM 4/28/2004 -0700, Justin wrote:
>Yep, your right....the wiring diagram looked like it did at first..but you
>would still need an "after-run" thermo switch.  Tripping a relay off a
>injector cooling fan thermo switch would not sevrve as a usful
>function....the thermo switch for the injector fan is rated at much higher
>temp than would be nessary for an radiator type cooling switch.
>If you have access to a wiring diagram, for any 5000 turbo or later 4000
>quattro...they all have seperate thermoswitches dedicated for after
>functions....probably for a reason...,
>Justin

Just to clarify a few things:

After run temp switch for 4kqs is mounted where injector cooling fan switch 
is located on turbo engines.  They're typically 95 deg. C  and run a -532C 
relay to limit run time.  The relay runs the rad fan only.

After run temp switch for NG engines is mounted on a small bracket on the 
opposite (driver's) side.  Crankcase ventilation plumbing prevents mounting 
of the usual mounting bracket.  The same relay (532C) is used.  The relay 
runs the fan in low speed through the built in fan resistor (Coupe GT) or 
through the resistor plate (Type 44).

Turbo engines trigger after run functions with a separate sensor switch 
positioned in the rear side of the upper coolant hose outlet.  The relay 
runs the rad fan AND the auxillary water pump.  Doesn't switch on that 
often in my climate.  Audi service info states that the aux pump turns on 
for a second when the engine first starts, probably to keep the impeller 
from freezing in position.  The relay used is a -571A relay.

Regards,





-Tony

'80 5KS
83 urquattro #DA900302
'85 4kq
'87 5kcstq
'87.5 coupe GT