Your speedometer on your 1991 Toyota Tercel doesn't work what could be wrong or how to fix it?

check on the tranny... there should be a cable that screws into the top of it... eather that part of the cable is broken orr... give the cable a little tug... if it slides out of its casing then you need a new cable... if its tight and wont come out then you need to look inside the tranny... and that's not fun...