Windstar A/C PROBLEM

1998 windstar 3.8 gl automatic .A/C Stopped working, so I checked compressor to see if clutch is engaging- it is not, so I disconnect the clutch terminal wires, then I hook-up some jumper wires from battery to clutch terminal, the clutch engages and the compressor starts turns, the a/c is cold inside van and works properly now. What should I replace? And where is it located? Please give full details. Thank you