We had a member here, many years ago now, with an ST variant who wanted an ambient temperature display - he could see when the light shined the right way on his instrument cluster that the item was supposed to be there.
So we met up one day, I had a look where the sensor was supposed to go (I had installed my own, because Australia didn't warrant ambient temperature displays when we barely knew what fire was and still chased after women with clubs). I found that the loom for this particular component was missing completely, couldn't find it at all.
Subsequent investigation revealed that pins 49 and 50 of the instrument cluster's main connector (see
this post) connect directly to the temperature sensor which is supposed to be a thermistor with a red package, gold tip (see
this post). In
this post you'll see that one of our members used a small computer connector to join the needed wires to the instrument cluster and ran them manually out through the firewall to a suitable location (in front of the air conditioning evaporator behind the grille is a small metal support bar and this is perfect).
So basically, your car may not have the wiring, but by running a pair of wires from the sensor into the instrument cluster you'll get it working.