This is the tensioner for an '01 caravan looking through the wheel well. You have to hold the tensioner in the released position to get the belt off the pully. I would highly recommend doing it from below.

 

Tizzy1, nice pic.

The last time I replaced a belt on one of these I hooked a strap to the box end of the wrench and anchored it on top with a piece of wood. Popped the new belt in and loosened the strap. Fast, easy, and no broken knuckles. I suggest using a quality wrench though. The open end of a cheap wrench can flex and come off.

 

After reading this I thought it's about time to replace mine besides that my idlers are starting to make noise and it would be nice to have a spare belt. Belt $21.99 (cheapo), upper idler $17.99 (goodyear), tensioner idler $19.99 (gates).

It took me about 20 minutes and I replaced the both idlers. I would highly recommend the idlers too. They are cheap and wear out almost as fast as a belt.

1. From the top get a 19mm wrench on the tensioner. Pull up and pull the belt off the top idler and alternator.

2. Remove the intake hose and fish out the belt. If you are replacing the tensioner anyways unbolt it with a 13mm wrench. It makes belt retrieval easier.

3. If you are replacing the upper idler do it now (15mm wrench). Also, this is a good time to replace the tensioner idler (13mm wrench) if not going with the complete tensioner.

4. Bolt the tensioner and idler back in. Make sure the tensioner is keyed in correctly.

5. Fish the belt down in. Lift the car just before the tire lifts. Unbolt the splash guard (1 10mm bolt) Reach up and get it situated on the lower pulleys and around the tensioner. Get back up top and pull the tensioner with your 19mm wrench and get the belt first on the alternator. A little more pull will get you under the upper idler.

6. Make sure the belt isn't binding up around the upper engine mount, replace the intake hose and splash guard bolt and you're done. Save the old spare along with a 19mm wrench for an emergency roadside repair.

 

Yikes, I wish I'd noticed there was a second page of replies to this question when I looked it up the first time. Still, reading the first page helped me get my head around what I needed to do. Putting a wrench to the protrusion on the tensioner is exactly how I ended up getting my serpentine belt back on after an alternator replacement on my 3.3L 2001 V-6 Dodge Caravan. Excellent drawing, Tizzy1. I did it from below, pushing up on the wrench and being VERY careful about my fingers. Now I'm thinking I should have replaced those idlers ... I'll likely use the belt method detailed by 2002Caravan when I swap them out. Thanks guys, this site is a great resource.

 

I found that a 10" cresent will fit on the back end of the tensioner and when rotating the tensioner the wrench handle can be slipped over the A/C clutch and it will stay there. This will let you have both hands free to replace the belt.

This may not work on all models.