Mercedes W123 Aux Fan

[pixelsblack009]

Hello!

I have a 240D W123 1983 (I think)
The Aux fan does not work I even left the AC on and the car running standing still for 15 minutes and its no good, I know the fan is good (I ran a positive wire to it and it ran)

It gets quite hot here in Sri Lanka and the AC does not seem to do much cooling with the fan not working, this is my dad's new car, its new to me so I'm not sure where the components are located
If you could tell me where the relays/sensors are located I can test them and pin point the problem
I've mostly worked on the /8

Thanks