Belt slipped off the tension pulley on my 92 ford E350 jamboree motorhome

SOURCE: Belt Tensioner located on 2000 ford Escort zx2

On the right side of the pulleys, there should be 3 top, middle, and bottom. The middle, smaller one, is the tensioner.

SOURCE: serpentine belt slips off idler pulley

The A/C pully is supposed to spin freely until the AC is activated to run.. The cranshaft pully does not. Replace the tensioner pully. The belt has to fit in between the grooves on the pullys.

SOURCE: Can't get A/C belt around pulleys on my 01 Chevy Tracker 2.5 V6

Removal & Installation

1.6L Engine
A/C Compressor Belt

1. Disconnect the negative battery cable.
2. Loosen the A/C compressor mounting bolts.
3. Pivot the A/C compressor towards the engine in order to relieve the tension on the belt.
4. Remove the A/C compressor drive belt from the pulleys.

1. Properly route and install the A/C compressor drive belt on the A/C compressor, the power steering (if equipped), and the crankshaft pulleys.
2. Adjust the A/C compressor drive belt to obtain 6-9 mm (0.24-0.35 in) deflection.
3. Tighten the A/C compressor mounting bolts to 13-20 f t. lbs. (18-28 Nm).
4. Connect the negative battery cable.

1. Disconnect the negative battery cable.
2. Remove the power steering pump and the A/C compressor drive belt.
3. Loosen the generator mounting bolts.
4. Pivot the generator towards the engine and remove the accessory drive belt.

1. Properly route and install the generator drive belt on the pulleys.
2. Adjust the alternator drive belt to obtain 6-8 mm (0.24-0.32 in) deflection for a used belt or 5-6 mm (0.20-0.24 in) deflection for a new belt.
3. Tighten the generator mounting bolts to 17 ft. lbs. (23 Nm).
4. Install the power steering and the A/C compressor drive belt.
5. Connect the negative battery cable.

1. Disconnect the negative battery cable.
2. Loosen the power steering pump mounting bolts.
3. Pivot the power steering pump towards the engine in order to relieve the tension on the belt.
4. Remove the power steering pump drive belt from the pulleys.

1. Properly route and install the power steering pump drive belt on the power steering pump and the crankshaft pulleys.
2. Adjust the power steering pump drive belt to obtain 6-9 mm (0.24-0.35 in) deflection.
3. Tighten the power steering pump mounting bolts to 22 ft. lbs. (30 Nm).
4. Connect the negative battery cable.

SOURCE: tension pulley for the Serpetine belt

The tensioner is the 3 1/2" pulley located between power steering pump and alternator down about 5" on front of engine. Does it have air conditioning?
If you need the diagram please post your email address and I will email it to you as I do not know how to post pictures on this.

SOURCE: 2002 Ford Escort ZX2 serpinten belt routing & tensioner pulley

go to www.gates.com on the lower right hand side under popular topics, click on timing belts, then on the left hand side click Parts Locator and Interchange, enter your cars info and the first page that comes up will show you a camera icon for a pic of how your belt is routed. The tensioner pulley is the one mounted on a silver arm, usually at the top. Hope this helps let me know.