[928uk] S4 Overheating - Temp Sensor Operation

[Paul]

Here's the section that mentions using the aircon to force the fans on:

*TROUBLESHOOTING THE COOLING FANS (‘87 AND UP CARS)*



Turn the ignition switch on, but don’t crank the engine. Turn the A/C on,
with the blower on speed 2. Both cooling fans should run at low speed.


I had a problem yesterday, thankfully resolved now - I don't have the
original plugs on the ends of the fan leads which fooled me into thinking
I'd connected the cables when in fact I hadn't


I used the email from earlier because it had some useful info at the
beginning, I didn't notice that it had been truncated


Paul

87 S4 Manual

On Wed, 5 Jun 2024 at 09:54, Paul R Smith via 928uk <928uk at lists.928.org.uk>
wrote:

> That's a big document, and I can't see what you refer to.
> But I'm a bit confused, the email you are replying to is from 2007. Do
> you have a current problem, or are you pre-emptively checking your fan
> system?
>
> Smiffy
>
> On 05/06/2024 08:17, Paul via 928uk wrote:
> > For anyone who needs an easy to read diagnostic guide, this is invaluable
> >
> > https://www.928gt.com/T-WallyHVAC.aspx
> >
> > However, the method he advises to force the fans to run does not work on
> my
> > car, probably because my aircon has lost pressure and is not operational
> at
> > the moment
> >
> > Therefore I made this by taking an old temp sensor, breaking off the
> brass
> > section, and twisting the wires together
> >
> > Then I removed the connector to the radiator temp switch and plugged it
> in
> > there, this forces the fans to run with the ignition on
> >
> > https://thumbsnap.com/i/JCzAYETX.jpg
> >
> > Paul
> > 87 S4 Manual
> >
> > On Mon, 21 May 2007 at 11:45, Paul<ukkid35 at gmail.com>  wrote:
> >
> >> Quote from EuroCarParts for:
> >>
> >> Rad Sensor (Fan Switch)
> >> Temp Sensor (I or II - not known)
> >> Thermostat
> >>
> >> £90, but at least they are all in stock. I won't know which temp
> >> sensor they have, Temp I or Temp II, until I see it though.
> >>
> >> Not exactly a bargain, but it's no fun when they're faulty.
> >>
> >> Paul
> >> 87 S4 Manual
> >>
> >> On 20/05/07, Paul<ukkid35 at gmail.com>  wrote:
> >>> No sign of it escaping from the overflow hose, but I hope that's where
> >> it's
> >>> going - where else could it go?
> >>>
> >>> Switching the aircon on seems to keep the temp under control, but there
> >> was
> >>> an initial very high reading after about 4 mins driving, which then
> >> dropped
> >>> to normal, I'm guessing was when the thermostat opened - perhaps there
> >> was
> >>> an air lock.
> >>>
> >>> I'm tempted to replace Temp I, Temp II, the Rad sensor and the
> Thermostat
> >>> all at once. In the past I would have been more frugal, but for once I
> >> can
> >>> aford to be a bit more extravagant.
> >>>
> >>> Paul
> >>> 87 S4 Manual
> >>>
> >>>
>