Which wire do you hook up an aftermarket tach to get a tach signal on a 94 gmc sonoma?

To hook up an aftermarket tachometer in a 1994 GMC Sonoma, connect the tach signal wire to the negative terminal of the ignition coil. This wire typically provides the necessary signal for the tachometer to read engine RPM. Ensure to use proper connectors and secure the wiring to avoid any interference or disconnection while driving.