Need under hood fuse box diagram for 1994 ford f150

Your radio fuse is not under the hood. It is in the dash panel on the left of the steering column. Y have to have two hots one constant for the memoty and one accessory that powers on the unit when your ignition is engaged. All you need is a test light to find the constant when the truck is off and the accessory that comes on with the key. There may also be an inline fuse in the dash that is blown. It would most likely be on the memory hotwire.