Just changed the aux belt and notice there was no guides on this forum so here is one.
Tools:
Car Jack
Axle Stands
3/8" rachet (preferable over 1 ft long for leverage)
13mm socket maybe
Tools to remove wheel
Tools to remove rear off side wheel liner
Parts:
5PK880 drive belt
Loosen rear off side wheel bolts, jack the car up, support with an axle stand, remove rear off side wheel and the wheel liner.
Now you should have access to the belt and tensioner:
20161015_111229 by Richard Fanders, on Flickr
pulley2 by Richard Fanders, on Flickr
I had to remove the trigger wheel sensor thing by undoing the two 13mm bolts:
pulley by Richard Fanders, on Flickr
The insert a 3/8" ratchet into the square on the tensioner to release pressure and remove belt.
tensioner by Richard Fanders, on Flickr
Reinstalling is the reverse. An easy job but lifting the tensioner requires big muscles when you only have a small tool.
Here are photos of the belt, new is bottom, slightly thicker and less shiny, hopefully it will stop slipping at full throttle:
20161015_100423_001 by Richard Fanders, on Flickr