[s-cars] Outside Air Temp (G17) sensor wiring problem

[Tom Green]

You should look at the diagnostics for the c/c system to determine  
what is shutting the a/c
off.  You will need to check the trouble codes in channel 1 and the a/ 
c on channel 53 IIRC
to look for specific sensors that signal shutdown.  The codes should  
be cleared after recording
them so you can determine which are current problems in subsequent  
readings.

http://12v.org/urs/Climate%20Control%20Channels%20&%20Codes.pdf

http://forums.quattroworld.com/s4s6/msgs/47427.phtml


Tom '95 S6
          '95.5 S6 avant
Knoxville, TN

On Wednesday, July 17, 2013, at 10:06 AM, Wayne Dohnal  
<wd43 at hevanet.com> wrote:

> My OAT reading has failed on-and-off occasionally for a few years. It
> went to hard-fail mode a few days ago.  It would be easier to ignore  
> if
> it didn't lead to the air conditioner refusing to operate when it  
> thinks
> the outside temp is below zero.  This is a 1994 urS4.  Looking into  
> it,
> the wiring diagram doesn't match what's in the car (not the first time
> that's happened!).  The diagram shows a brown/yellow wire connecting  
> to
> the G17 sensor via the orange connector in connector station 1 under  
> the
> dash.  The reality is that there is a brown/yellow wire going through
> connector station 1, but at the connector for the G17 sensor it's a
> brown/white wire.  At connector station 1 the wire from the sensor  
> shows
> an open circuit, and at the G17 connector it shows about 2k ohms to
> ground.  I'm making a repair by adding my own new wire from the G17
> sensor to connector station 1.  This makes the OAT readout work
> correctly.  My question is: (1) Does the brown/yellow wire change to
> brown/white somewhere inside the wiring harness, and the internal
> connection has failed?, or (2) Is there more circuitry here, totally
> missing from the wiring diagram?
>
> Wayne
> 1994 S4