I took the details directly from the ford workshop manual, and pin 20 is EARTH, a shared earth with the lambda sensor, the listing says "IT COVERS BOTH THE 2WD AND 4WD COSWORTH"
Having repo'd cars for 3 years cossies are a piece of piss to steal as are 95% of pre 200 cars, but even some 2011 cars can be opened with a lighter, most likely around 1 million cars on our roads from vw/seat/skoda/ford to name a few, though it does take about oooh 5 seconds!!
tabetha