Where is the speedometer cable on a 1996 Toyota Tercel?
On top of the trans close to the firewall and engine block.
Look where the shift cables (manual trans) come out of the firewall.
1996 and newer have an electronic speedometer and a vehicle speed sensor that operates your electronic speedometer and also sends a signal to the powertrain control module (PCM) The PCM uses this signal to control several different functions of the engine and transmission.. Your 1996 doesn't have a conventional speedometer cable.
This is very common on the 1996 Ford Escort unfortunately. Basically the speedometer cable has to be re-greased or the speedometer has to be replaced with the older 80mph model. Both "fixes" require disassembly of the dash to get to the cable/speedometer. See the ford escort owners association for more details/instructions.