Its just a changer lead, I'd check your car if first, i know i have a mk2 and the changer lead was still installed (however i have a mk1 interior)
in the boot, passenger side, pull down the side wall carpet and have a look around, the end is usualy covered in grey foam.
If not you will need to install this cable, the easiest way to do this being, run the cable from your headunit behind the dash into the passenger footwell,
Remove the plastic at side of door

be very patient and careful as these snap very very eaily (£12 form fiat)
under this and the carpet are already wires clipped together slot it in there and follow this all the way into the boot or under the rear seats where you will find a hold covered by carpet where the changer can be mounted (check changer fits before cutting carpet)

Bravo my son Bravo!!
