Vss I run them with and without, I can’t tell a difference. The sensor is in the gearbox for both Focus and Mondeo. Reading I’ve done says it cuts fuel on over run. This is how they make pops and bangs maps by adding fuel on over run. ( and timing ).

From memory, clutch switch is a normally closed switch. So unconnected it will think the clutch is down and increase the rpm. Only a little. You can connect the pin to the sensor common earth ( brown )

if you you tell me if the loom / ecu is Focus or Mondeo I can tell you what pin is what.