The fuel pump has dual circuits. One circuit activates the pump during start mode. Upon start and running, the task is transferred over to the alternator. Unlike many vehicles, the pump does not power up if the key is only turned to the on/run position. Let me know if the fuel pump circuit isn't in those illustrations so I can upload them to you. The following was easier to copy from http://forum.planetisuzoo.com/ than to type it myself.

There are 2 fuel pump circuits. Main one keys from the alternator after the engine is running. The other one bypasses the main one when the starter is turned to pressurize the fuel system until the engine is running and the alternator is putting out voltage. If they are checking in the start mode they are missing the big picture. This stuff never fails the test in start mode unless the fuel pump is bad. The engine kicks and sorta starts then dies shortly after you let go of the starter because the alternator is not taking over. The test is simple. You need to remove the fuel pump relay and jumper 2 terminals that will send juice from a constant hot to the fuel pump. If the truck runs it is the alternator! Easy test. It has been written up many times with a picture that shows you how to jumper it. Search for the one of the posts and do the test. If it then doesn't work you can move on to looking for other problems. Alternators do not like to get wet. Do the easy tests for common problems 1st and go from there. 9 out of 10 times it is a common failure. There are 2 fuel pump circuits. Main one keys from the alternator after the engine is running. The other one bypasses the main one when the starter is turned to pressurize the fuel system until the engine is running and the alternator is putting out voltage. If they are checking in the start mode they are missing the big picture. This stuff never fails the test in start mode unless the fuel pump is bad. The engine kicks and sorta starts then dies shortly after you let go of the starter because the alternator is not taking over. The test is simple. You need to remove the fuel pump relay and jumper 2 terminals that will send juice from a constant hot to the fuel pump. If the truck runs it is the alternator! Easy test. It has been written up many times with a picture that shows you how to jumper it. Search for the one of the posts and do the test. If it then doesn't work you can move on to looking for other problems. Alternators do not like to get wet. Do the easy tests for common problems 1st and go from there. 9 out of 10 times it is a common failure.

Additionally, read this next thread and scroll down to the pic showing how to jump the fuel pump relay.

http://forum.planetisuzoo.com/viewtopic.php?t=13176