Need Help. 99 Mustang Problems..

Is anything else not working? Check the big 40 amp fuse in the engine compartment fuse box. If you're leaning over the drivers side fender looking at the fuse box , its the second big 40 amp fuse from the top. Verify that one is not blown out. It controls function such as wipers and power windows, plus the ignition chime.

Suspect bad GEM or ground

MustangLX-5.0, starting in 1999, the Mustang was re-designed. The electrical circuit schedule is completely different from <1998. The number of circuits was almost doubled. There is no 40 amp main engine compartment fuse.

This sounds like a possible Generic Electronic Module (GEM) problem. The module is either bad or has a bad ground. Has any recent radio work been done? The radio and GEM share the same ground on the Left hand center console area. Any water damage?

Luggage rel F2.25(25a) GEM
Wipers F2.26(30a) GEM for delay function
RKE F2.19(15a) GEM
RKE F2.25(25a) GEM
Warning F1.10(30a) GEM
door locks F2.19(15a) GEM

There are several fuses involved (no single common fuse). Note: F1 is the BJB and F2 is the CJB.

The GEM is somewhat $$ and IMO you should be positive this is not a bad fuse (or two) before replacing anything. If visually checked from above, it can be hard to tell if a fuse is actually blown. Suggest pulling the fuse and checking with an Ohm meter.