I just received a copy of the 1996 ford service cd and came across this and thought it was interesting. Has anyone ever heard of this or actually heard this?
Shift Indicator Tone
When the vehicle reaches a speed of 120 km/h (75 mph) in a gear other than overdrive, the powertrain control module (PCM) (12A650) sends a ground signal through Circuit 462 (P) to the integrated lamp control module. The integrated lamp control module then emits a high pitch tone (refer to Powertrain Control Module in the «Powertrain Control/Emissions Diagnosis Manual»).