The tachometer on your 1995 Toyota Corolla is contained on the instrument panel on the driver's side of the Corolla, just above the steering wheel. To hook up a new tachometer, you need to remove the whole instrument panel and install a new one. The tachometer is actually built into the instrument panel so it will not be possible to simply remove...
M/F Pull the Corolla's hood releasing lever to lift up the hood. Using a socket wrench, disconnect the Corolla's battery by removing the negative terminal cable.
M/F Remove the three screws on the upper portion of the dash above the instrument panel with a cross-head screwdriver.
M/F Pry off the upper dash from the instrument panel with a flat-head screwdriver to access the instrument panel.
M/F Uninstall the instrument panel's four retaining screws, making sure not to lose them as they will be required to install the instrument panel.
M/F Pull out the instrument panel and remove its three electrical connectors and pull it out of the Corolla.
M/F Install the new tachometer by attaching the three electrical connectors to the new instrument panel that contains the tachometer. Reinstall the four instrument panel screws.
M/F Reattach the upper dash and its screws. Reconnect the negative terminal to the battery. Close the hood.