A 1-1/4-inch hole was drilled...
A 1-1/4-inch hole was drilled in the firewall and the supplied grommet was installed. The front wiring harness was then fed through the hole.
The front master harnesses consisted of a headlight and starter/ignition harness, while wires for gauge sending units, fan wire, electric choke wire, coil wire, etc., are also supplied.
The wires were then routed to the appropriate connections via the instructions. After the individual wires were cut to the desired length, the appropriate terminal ends were crimped in place. (Note: There is a correct and an incorrect way to crimp the terminal ends. The seam in the terminal end should face away from the dimple portion of the crimping tool, thus the dimple, or the part that crimps against the wire, is solid.) Heat shrink tubing was used at each terminal end. Shrink tubing adds strength to the connection, makes the connection waterproof, and adds to the professional look of the finished wiring. (Note: In most cases the shrink tubing will need to be slid over the wire in its pre-shrunk condition prior to installing the terminal end.)
We chose to build a gauge wiring harness rather than connect the wires directly to the gauges. Since gauges normally are removed from the front this allows the gauges to be installed and removed by disconnecting the gauge harness from the electrical harness, instead of laying on your back, under the dash, installing or removing the nuts that secure the gauge wires. The construction of this harness only required us to cut the individual wires and install bullet-style connections to the ends of the cut wires. The reconnected wires remain color-coded and marked.
We split the front wiring...
We split the front wiring harness into smaller harnesses, a headlight harness, a fan harness, an alternator harness, a starter solenoid harness, and an ignition and gauge-sending unit harness.
After installing the gauges in the dashboard, with the gauge wiring harness attached, we routed the various gauge wires (temperature sending unit, oil pressure sending unit, etc.) that are part of the wiring harness to the gauges.
The electric speedometer wires were separated and paired (twisted together) per the gauge instructions. One of the twisted wires was connected to the sending unit in lug on the speedometer, while the other wire was attached to the ground lug. A separate chassis ground was run from the speedometer ground lug to a chassis ground. The speedometer instructions suggested that the twisted wires not be run with other wiring, as that may cause interference with the electric speedometer.
The ignition switch was purchased from a local parts store. The switch is rated at 30 amps, and has the power-in, accessory, ignition-on, and start terminals. Per the wiring kit instructions the appropriate wires were connected to the marked terminals.
The harnesses were neatly...
The harnesses were neatly wire tied every 5 to 6 inches; plan on using a number of small wire ties.
An off/on/on/on light switch, also from a local parts store, was selected for the headlights. This switch allows parking lights at the first on, headlights at the next on, and bright headlights at the final on. This eliminated a floor-mounted dimmer switch. The switch also had a terminal for the taillights and we ran our dash lights off of that same terminal.
The rear section wiring harness was run along the edge of the passenger floor through a grommet-filled hole in the seat riser and out of the floor of the pickup truck cab. Obviously on a coupe, roadster, or sedan you would run the wires through the trunk area. The rear wiring harness consisted of taillight/brake light, license plate light, and the fuel sender gauge wires. Since we are utilizing an electric fuel pump we also included a switched fuel pump wire. Since we were not running a heater (we live in Florida) we used the fused heater wire in the wiring kit as the fuel pump wire.
The fan relay was mounted under the seat and wired per the instructions. We also added an on/off switch on the ground side of the relay. This allows us to manually turn the fan off should we choose to do so during engine maintenance. We chose to run the fan whenever the engine is running; we may add a temperature controlled fan switch at a later date. We also installed a relay and a switch on the fuel pump; this too was mounted under the seat.
Terminals should be placed...
Terminals should be placed in the crimping tool with the seam in the terminal opposite the protruding die on the crimping tool. This will allow the die to drive the side opposite the seam into the wire instead of opening the seam in the terminal and making a weak and poor connection.
Adhesive-lined 3M heat shrink...
Adhesive-lined 3M heat shrink tubing was used on all terminal ends, making a strong, waterproof, professional-appearing terminal.
We cut each wire in the harness...
We cut each wire in the harness that was designed to go to the gauges. By installing bullet-type male/female connectors on each end of the cut wires we were able to create a separate gauge wiring harness, allowing the gauges to be easily installed and removed by disconnecting the wiring connectors (bullets).