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. Crimp it with the crimping tool. Remove the nut on the negative side of the coil, insert the wire loop and re-install the nut and tighten.
Attach the red wire to a terminal that has power only when the ignition switch is on (in the fuse block). Check the terminals with the voltmeter to find a terminal that is switched. Attach a blade terminal on the end of the wire, crimp it with the crimping tool and insert it into the terminal on the fuse box.
Attach the yellow wire to the same terminal as the red wire (which would turn the light on as long as the engine is running) by inserting the yellow wire in the same terminal connector as the red wire and crimping both of them together. This is the easiest method. The other method requires locating an instrument light wire behind the fuse block. Look for the fuse for the panel lights. Once located, remove the fuse panel by removing the screws and turning it over. Remove the fuse and turn the lights on. Check the two sides of the terminal for power. The side that has no power with the fuse out is the side that the yellow wire to the tach is to be attached to. If the wire is installed on the terminal that has the power it is not fused. If it is installed on the non-power side, the power must go through the fuse to get to the yellow wire, making it fused. Cut the wire and install the connector on the fuse side of the wire with a cylindrical butt connector. Strip the insulation off the yellow wire and do the same for the other side of the wire you just cut. Wrap the two ends together, insert them into the butt connector and crimp it with the tool. Re-install the fuse block.
Connect the last black wire to a good ground using a loop terminal connector.
