That is not how my fuses are listed in the owners manual. Are you saying 19 and or 21?
I don't know what to tell you. I gave you the fuse numbers EXACTLY as they are listed right out of the official Ford wiring diagrams. Further from spot checking various model years they are the same at 2000, 2002, and 2004. The only difference I noted was for the 2000 model year the BJB fuse is labeled "power point" instead of a number. But it's in the same spot.
If you are looking at the incorrect fuses, this might explain why you are not able to trouble shoot the circuit.
Or you could assume that your fuse numbers is correct and perform the tests given and go from there.
Or you could simply test all of the fuses in the engine bay (BJB=F1) and Central Junction Box (CJB=F2) then you would know for certain.
Or perhaps your Mustang is different. Which if true means ^^^See above^^^
Bottom line. IF the fuse is good then the problem is either:
The socket itself is bad
the ground is bad.
there's a wiring fault between the fuse and the socket.
2003 GT Convertible (sold & missed)
2000 GT coupe (Craigslist project. Fixed. Now my DD). Windsor to Romeo swap.