All 172 Ph1s, All 172 Ph2 Cups and (some) regular 172 Ph2's ran speedo sensors in the back of the box, which drive the dash..
Some regular Ph2 172's, and all 182's use the ABS
Bloooors and Jesus's 172's had the sensor from the back of the box to name a few...
To the OP - the sensor can be had from Renault for under £30, then its just a 3 pin connector. Power, Earth and Signal. Signal runs to a pin on the dash/clockset..