Unfortunately, the Toyota part number search engines I found (see below) aren't even close in utility to those I've used for other makes ()- so there must be better 4Runner parts diagram sources than what I have listed below.
Need to know how to find Toyota part numbers? Vehicle part numbers make it easy to locate specific parts. Manufacturers assign numbers to each part they create. Automotive parts stores, mechanics and dealers use the number to locate parts when repairing your vehicle. To find Toyota part numbers you can use a number of resources. Contacting an auto mechanic or an original equipment manufacturer combined with online resources yields the best results.