2 weeks ago I replaced the dash in my 2000 Mustang. WARNING! I recommend getting the entire dash with installed wiring harness from a junkyard. I did not. Removing an old harness and replacing it into your present dash will have you diagnosing electrical problems for a while. Dash with harness removal and reinstallation as a complete unit is fairly straightforward. I would be happy to answer any further questions on the process.
Another problem I ran into was I lost all turn signals, brake lights, 4-way flashers, and cruise control. The problem was I accidentally stressed the wiring harnesses on the steering column while removing it and caused the harnesses to come apart on the top of the multifunction switch. The connections are located under the plastic steering column covers on the top surface of the multifunction switch. Part of removing the upper plastic piece is to remove the ignition key/lock from the column. Turn the ignition to run, insert a thin punch/screwdriver into the smaller hole in the lower plastic housing under the ignition key, push up, and remove the key/lockset.