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

[Wayne Dohnal]

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