[V6-12v] Radiator Fans not switching in correctly...

[Tom Christiansen]

James,

The resistor pack looks like an L-bracket with three lugs on it. I'm
guessing there are two resistors in the pack, but only one of them is
used on my car. Just follow the wiring harness from the fan and you'll
find it.

Tom

On 8/29/06, James Whitehouse <james_whitehouse1 at yahoo.co.uk> wrote:
> Tom,
>
> Thanks, that's most helpful, I can limit my efforts to the thermo-switch on
> the rad, and the 'resistor pack' you describe. I'd never come across that
> resistor pack. I'll have to see if I can find it! I'll try looking
> underneath the battery somewhere and have a poke around, as it sounds like
> the symptoms you're describing are what I'm experiencing. Any idea what the
> part no would be for that resistor pack?
>
> Cheers,
> James
>
> > -----Original Message-----
> > From: Tom Christiansen [mailto:tomchr at gmail.com]
> > Sent: 29 August 2006 21:04
> > To: James Whitehouse
> > Cc: v6-12v at audifans.com
> > Subject: Re: [V6-12v] Radiator Fans not switching in correctly...
> >
> > James,
> >
> > There are three thermosensors/switches in the system:
> >
> > 1) Engine coolant temperature sensor (ECT) in the hard coolant line by
> > the EGR valve. Port side, aft of engine. This is used by the ECU.
> >
> > 2) Temperature sensor, switch on the starboard, aft side of engine by
> > the ISV. This feeds the gauge on the instrument cluster as well as
> > turns on the high-temp warning light.
> >
> > 3) Thermoswitch in the bottom starboard corner of the radiator. This
> > one controls the rad fans.
> >
> > Even though I have A/C, my car (1994 90 S, AAH engine) only has one
> > rad fan. The speed of it is controlled by the thermoswitch as well as
> > a resistor pack mounted on the port side, forward subframe. More or
> > less directly under the battery. If the resistor pack is fried, the
> > fan will usually kick on at high-speed only. Resistors normally fail
> > open so you'll get no fan action until the trip point for high-speed
> > is reached. My rad fan turns on at low-speed when  I turn on the A/C.
> >
> > Hope this helps.
> >
> > Tom
> >
> > On 8/28/06, James Whitehouse <james_whitehouse1 at yahoo.co.uk> wrote:
> > > Guys,
> > >
> > > Anyone know the fault finding procedure for the radiator fans on this
> > > engine? My engine manual doesn't cover this, for some reason (why?). I
> > only
> > > have fault finding for the ignition system, which covers the coolant
> > temp
> > > sender (G62), which feeds the Control Unit.
> > >
> > > However, I know that there are two other 'thermo switches', one being
> > the
> > > thermo switch that plugs in on the bottom left of the radiator housing
> > > itself, and another (F76) which sits on the large coolant pipe on the
> > left
> > > rear of the engine (as you look at it from the front of the engine bay)
> > > which I know feeds the dashboard temp gauge, but I believe may also have
> > > something to do with the rad-fan timing, etc.
> > >
> > > There's also a relay or two in the fuse box and a couple of fuses, but I
> > > don't have enough detail on what the two thermo-switches actually do to
> > know
> > > where to start.
> > >
> > > The symptoms are as follows:
> > >
> > > - Engine waits until it's one mark beyond the 'normal' temp mark (the
> > more
> > > distinctive 'centre' thicker splodge of white mark on the dash), then
> > both
> > > fans kick in (full speed?) for about 20 seconds. They then turn off
> > again
> > > without having cooled the engine.
> > >
> > > I'm guessing that a) first speed fans aren't working, as I remember them
> > > kicking in before that mark, and staying on longer, then 'speed 2'
> > kicking
> > > in when sitting in traffic for ages, bringing it down to 'speed 1' temp.
> > >
> > > If anyone has info, or fault finding for this system, could you let me
> > know
> > > please?
> > >
> > > TIA
> > >
> > > James
> > >
> > > --
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> > >
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