2001 Clio 1.2 16v strange connector hanging down rear of engine

Hi guys - first post (although I’ve been poaching advice since buying a Clio two weeks ago). It’s a real heap and needed lots of work despite having a full MOT. This morning while checking that nothing had fallen off since yesterday I noticed a yellow connector block hanging on a lead down the rear of the engine and over the gearbox - it’s not connected to anything but just hanging in space. I’ll attach a photo if I can - anyone know what it is and should it be plugged in to anything?

[IMG]<a href="http://ift.tt/1XZkkzA; target="_blank"><img src="http://ift.tt/1XZkneC; border="0" alt="Clio connector hanging loose photo DSCF3758_zpsfxvgiwwu.jpg"/></a>[/IMG]

2001 Clio 1.2 16v strange connector hanging down rear of engine