5S-FE MK2 Non-Turbo Engine Double Din Head Unit Speed Signal Lead

5S-FE MK2 Non-Turbo Engine, pink, wire, head, double, lead, signal, speed, unit, conclusion, guessing, color, located, input, http://i48.tinypic.com/2nsc2zo.jpg, http://i46.tinypic.com/a4bh44.jpg, http://i48.tinypic.com/aui34h.jpg, instructions, speedometer, mechanical, electric, planned, install, brand, wires, diagrams, indication, multiple, checked, supposedly, connects

so im trying to install my brand new nav double din head unit into my 93 mr2 NA. i have everything planned out and all the wires set EXCEPT 1! it happens to be a pink wire which supposedly connects to the mr2 speed signal lead. i have checked multiple diagrams with no indication of where it is located and what color it may be (maybe pink im guessing) but then ive come to the conclusion that our mr2 have a mechanical speedometer not an electric. does anyone have any input on this?