Hey all. I have a '97 with a 5.4. I have an aftermarket audio system installed in my truck and I am having trouble with it. Installed is a Sony head unit in place of the factory unit. I was driving along one day and the radio just went POP! I pulled the head unit out of the dash to see all the fuses still in tact. I then went to the fuse box under the dash on the driver's side, everything was still in tact. I then went to the power distribution box under the hood, everything was still in tact! So I started to scratch my head. Now I am an electronics technician by trade and I know how to t-shoot just about anything. Here is what I have. I have switched power, meaning my ignition power is there when the key is turned. I have ground. I do not have my constant power going to my radio. I have checked all fuses to no avail. I finally checked my wiring diagram in the Haynes repair manual and there is an EXTRA fuse box somewhere that I cannot find! Does anyone know where this extra fuse box is inbetween the power distribution and the radio? I cannot find it! I NEED MY RADIO BACK!

 

My 97 has the fuses in three spots. One is in the dash to the left of the steering column, the second is in a plastic boxmaybe 7 by 9 inches located behind the air cleaner housing. The third box is smaller and rectangular shaped. It is behind the larger box that is behind the air cleaner. It sounds like you have already looked at the first two boxes.