I have a 90 LS400, The speedometer stopped working last week, I heard a noise a type of a click sound coming from the drivers door side which sounded like a side mirror when they get stuck. the gauge is a dial style , how do you repair or replace the cable if its broken and how do you get in behind the dash. I know the car has a few speed sensors do they fail and could they create the problem, or is it most likley the cable.