In absence of a published manual (as far as I'm aware) for '97 Celica ST, I wonder if anyone with ANY model can help identify troubleshooting locations as I'm at the mercy of a garage who have the policy of just "replace the part rather than diagnose the problem" and these parts are rare so expensive. I'm pretty certain it's a wiring fault as there was no "faulty" reading until one journey speed ceased to register on odometer and speedometer completely. Fuses checked, although I haven't checked the 25amp fuse yet (as I don't know which one until I have a manual - the fusebox doesn't specifiy speedometer on its list).
Also, where would wiring be at gearbox end to check over?
If ANYONE with any model has advice, that will completely be useful.