How Do You Install An RPM Gauge?
When installing an RPM gauge — better known as a tach — short for Tachometer, the unit must be set on the backside to the number of cylinders of the vehicle. Read the instructions for the tach — some have a switch and some have three wires, which are for a V-8. One wire would be cut for a six-cylinder and two wires for a four-cylinder. Read the instructions because they all vary a little as to the procedure. Locate the tachometer in the desired location and attach with the hardware supplied with the kit. Separate the four wires. The green wire is the tach sender wire and is to be attached to the negative terminal of the coil. Find a nice location for the wire to pass through that looks good. The wires can be concealed with wire loom to look nice. Run the green wire through the firewall by inserting it through one of the rubber grommets in the firewall. Pull the wire from the engine side and run it along the firewall to the coil. Install a wire loop connector on the end of the wire.