Old thread but these things are still very relevant today - or at least earlier this week concerning my 2.4 Jtdm Spider with 45,000 mls on clock! The dreaded Aux Pulley is on drivers side of engine low down. The symptoms of failure are smoke, burnt rubber smell, clattering noise of slack belt followed by wonderful peace and quiet with alternator not charging warning and no power steering!
Action: look down side of engine and try and extricate the aux belt and see if bottom pulley still hanging in there. The belt may well have suffered no damage but it has to be got out unless it fouls other important moving parts. This direct approach did not work for me so I took off offside front wheel and then two screws on inspection cover on inside of wheel arch. This revealed pulley with its rubber part totally destroyed and burnt lying loose. The metal centre was still firmly secured on the crankshaft. Remove broken pulley and aux belt.
Car is then drivable for the range of the battery. Mine did 18 miles with lights and radio on (it refused to turn off!)! In daylight the car might do twice that on a full charge!
Fit new pulley (needs special tool of course), test all spinny wheels (a/c, power steering, alternator) and tensioners and refit belt.
Cause: I think the pulley becomes stressed when power steering is under heavy load when manoeuvring car about in very tight carparks or driveways. I am hoping new pulley is stronger but I shall be doing more reversing just in case it isn't!