Serpentine belt diagram fo 03 chevy s10 4.3 ltr, v6, I do not know the belt routing.

Go to www.gates.com , click on the Parts Locator & Interchange link on the left, put in your vehicle information, after you have put in the engine size look below and find the serpintine belt for you application, ie. w/ac or w/o ac, click the camera icon and there is your routing diagram, hope this helps, let me know