[s-cars] Coolant fan trying to kill the battery

[Tom Green]

> On  Wed, 29 Oct 2003 20:02:11 Sandy Sligh sends:
>
> To: s-car-list at audifans.com
> Subject: [s-cars] Coolant fan trying to killl the battery :)
>
> This has happened very rarely, like maybe once in a 3
> or 4 months: The coolant fan runs once the engine is
> shut off and will continue to run until the battery is
> drained far enough that the fan won't spin nor will
> the starter crank.
>
> So I crack open my Bentley vol. 3 and scour the
> electrical diagrams for a possible answer. Now, I have
> a 1993 S4 Canadian which is actually a 1992 model.
>
> Diagram X100 (92-93 S4) show that if I were to pull
> the relays sitting in positions 2 and 3, I should be
> able to open the circuit that powers the motor. While
> in a discharged state, I hook up the S4 to a jumpbox,
> lo and behold, the coolant fan spins up. I reach in
> the relay panel and yank out the two relays sitting in
> positions 2 and 3. The fan keeps running...grr.
>
> (But wait, I notice there is a relay in position 1.
> Why is there a relay in position 1? According to
> diagram X31, the layout of the relay panel, "1" should
> be open for the 92-93 models...)
>
> I pull out the mystery relay and the fan stops. YAY. I
> no longer have to jump start the S4 in the morning and
> afternoon anymore. But what did I disconnect?
>
> Now, there is a relay in position 1 in the 1994
> S4...well, there appears to be two groups of 1994 S4
> diagrams.. i'm confused.
>
> Anyone have any input? Are the diagrams for the 92-93
> S4 incomplete?

Sandy,

This is Aux relay panel I (under hood ) ?  That is location (position
1)  of the after-run coolant fan control relay for my '95, and that
relay controls the fan in all three modes, after-run, over-temp, and
air-conditioning.  It is probably ok.  There are three circuits that
control the fan operation, but the low speed operation after shutdown
is probably the after-run circuit.  The aux relay panel III in the pass
kickpanel has a turbo coolant pump control module relay that causes the
fan and pump to run for after-run mode.  Mine had the J155 module 447
965 571 A  contacts fused together causing the after-run not to cease
after 10 minutes.  Check the aux pump also ( by feel ) .   If it is
running also, go to the kickpanel (read how to remove the hidden screw)
.  There are archives on after-run, aux coolant pump, fan, etc , and
SJM's site may help supplement the Bentley.  I do not pretend to
understand the complexity and interactions of these circuits.  HTH

Tom '95 S6