The injector driver module is on the drivers side inner fender on the 95-97 trucks I dont know if they are in the same place on the newer trucks or not.Grey/silver box looks just like a pcm.Hope this helps
i have a 2001, it is located under inner fenderwell on drivers side. remove well right above tire and look up. it has awire harness with a bolt holding it in. remove that and 2 more bolts will release module. it is close to drivers door.