For a 2004 Silverado Ext Cab Z71 4x4: Early in September, I asked if there was a guide for identifying those 3-digit codes found on the Service Parts tag in the glove box. I recieved one reply saying I had a Z71 package. Yes, I know. I would like to find out what else was factory installed on this used truck, as I am getting some odd electrical reactions. My remote lock fobs bring up Driver 1 or Driver 2, yet there are not controls on the door or steering wheel. Thanks.