hi fox the ecu for the windows is located in the passenger footwell small black bolted up i done mine a couple of years ago it has 1 easy nut to get to and 1 awkward nut so i undone 1 and broke the rear lug it still goes back and holds properly,it does say window lift ecu or similar on box if you remove it carefully prise out the centre piece from memory its held in by 4 little lugs but the centre piece comes out easy enough check the circuit board and im sure you will find 2 desoldered joints,resolder and bobs your uncle,my rear windows did not work when cold odd but true worked a treat and its an easy fix so give it a go save some pennies,all the best tiga