I need diagram for serpentine belt installation on 1999 jeep wrangler.

http://serpentinebelthq.com/1991-jeep-wrangler-yj-4-0l-serpentine-belt-diagram/ her is a link for you to a diagram. I hope this helps

which engine do you have?

this is for a system with a/c. If you don't have a/c let me know and I will get you the correct one but i'm sure that you have a/c and power steering.

If there isn't a belt routing diagram somewhere under the hood, go to your local library and check out a vehicle specific repair manual to find this info.

You can also purchase these manuals at any major chain auto parts store (Pep Boys, Advance, Auto Zone, O'Reillys' etc.)

A chilton's repair book at an auto parts store will have this.

Adjustment is made by loosening the power steering pump. There is a transverse long bolt (jack bolt) right under the pump that is used for adjustment.

Click of the following direct, Free Link. It has several Serpentine Diagrams, including the one for your 1998 Jeep Wrangler 4.0L In-Line 6-Cylinders based upon your Engine Options (AC/No AC, Power Steering/No Power Steering, etc.).
The Link Page ALSO has the 2.5L In-Line 4-Cylinder Serpentine Belt Diagrams with their various engine options.
Included are the with AC / without AC Routing.

Let me know if this helped, or if you have additional information or questions. Feel Free to contact me at FixYa.com!
http://www.2carpros.com/car_repair_information/year/1998/make/jeep/model/wrangler/1998_jeep_wrangler_drive_belt_routing_diagram.htm

most have a "jack screw" under the power steering pump. You loosen the pump mount bolts and adjust the screw underneath to tighten or loosen it.

1997 JEEP WRANGLER - L4 2.5L 150ci GAS FI N P
Belt Routing Diagram Multiple Accessory, w/A.C.




More details in DAYCO Catalog

I hope help you woth this (remember rated this help).

you have to pull on the tenssionner, and sould be a diagram right under the hood. if not, go on google and write serpentine diagram and you be able to see a jeep diagram!