During our visit to the annual SEMA Show in Las Vegas last November, we bumped into Bobby Cross, from Painless Performance in Fort Worth, Texas. Bobby took us aside to introduce us to his affordable, fully compatible main-wiring system for vintage Mustangs. The Painless system ties into the early Mustang's factory switches and components without a hitch. It has a terrific fuse box that installs in the same location as the original fuse box. What's more, the Painless fuse box offers additional positions and circuits for accessories.
We're going to show you the Painless Performance No. 20120 12-circuit wiring system for '65-'66 Mustangs. (There are systems available for '67-'68 Mustangs as well.) This is an exceptional, high-quality wiring system designed to bring your Mustang's 40-year-old electrical system into the new millennium. It can tolerate extremes of heat and cold, and each wire is the proper size for the expected load. In addition, the system enables you to run lots of accessories without overloading it.
The Painless Performance Mustang kit consists of the main wiring harness with fuse box and courtesy-light wiring; taillight and fuel-sending harness (integral with main harness); headlight/alternator harness, engine/starting harness; parts kit; Maxi-Fuse with holder; rubber grommets; two packages of nylon tie-wraps; 12 instrument lamps; and eight harness mount clamps.
This is the Painless Performance...
This is the Painless Performance main wiring loom that goes under the dashboard. Think of this as your Mustang's nerve center. All harnesses plug into the main wiring loom. Included is a modern, high-tech fuse box (with easy-to-replace fuses) that mounts in the same location as the factory fuse box. The harness plugs into all of your Mustang's switches to completely replace your Mustang's original wiring system.
These weatherproof connectors...
These weatherproof connectors keep out moisture and corrosion. Since they're sealed tightly when connected, there is little chance of an open circuit. These connectors are easy to connect and easy to disconnect. What's more, a clean connection eliminates any chance of high resistance to the flow of electricity. High resistance creates heat-and fire.
This type of plug penetrates...
This type of plug penetrates the firewall where the Mustang's factory bulkhead connectors reside. Again, this plug is weather-tight and safe. The opening in the firewall must be carefully cut to the dimensions of the template included in the kit.
Like your Mustang's factory...
Like your Mustang's factory wiring, the Painless system disconnects at key locations, like the firewall. The main wiring loom under the dash has a female multiplex connector at the firewall. This is where the firewall-to-headlight loom connects. The firewall-to-headlamp loom handles all underhood power. It ties into the voltage regulator, headlamps and parking lamps, horns, starter solenoid, and alternator/generator.
This is the system's main...
This is the system's main power feed from the battery to the main wiring loom under the dashboard. Power begins at the red 10-gauge lead, passing through the Maxi-Fuse terminal, then entering the electrical system, just like the factory lead. This harness connects to the main wiring loom at a firewall bulkhead connector behind the engine.
The instrument panel gets...
The instrument panel gets its own wiring harness that consists of instrument lamps, gauge power leads, and turn-signal lamp connectors.
Painless makes this job easy,...
Painless makes this job easy, with something for everyone. If you have a Falcon-style instrument panel (standard for 1965), there is a single turn-signal lamp (center) and a charging-system lamp (right). If you have the five-dial instrument panel ('65 Interior Décor and GT Equipment groups, and all '66s), there is a dual-lamp harness for left and right turn signals. Believe it or not, it's impossible to connect any of it incorrectly.
Those with '64 1/2 Mustangs...
Those with '64 1/2 Mustangs will relate to this horn relay. When you press the horn ring, power flows through this relay two ways. Power from the horn switch energizes the electromagnet inside, which brings the contacts together, carrying power from the battery to the horns. The relay (also called a solenoid) carries the heavy electrical load instead of the horn switch.
Painless doesn't leave you...
Painless doesn't leave you out in the cold. This kit is equipped with plenty of connectors and zip ties to cover the installation. However, we cannot guarantee enough connectors if you ruin a few along the way.
To do this job correctly,...
To do this job correctly, you need the tools of the trade. Use a wire stripper and crimpers for best results. Keep plenty of the right size butt connectors and eyelets on hand just in case you squeeze too tightly and ruin a few of them.
When you join connectors with...
When you join connectors with wires, squeeze the crimper just hard enough to secure the wire. Make sure no copper wire shows outside of the connector. Ideally, you will solder these connections.
Painless Performance provides...
Painless Performance provides easy to read and understand instructions, including diagrams that make installation a snap. This is the headlight switch illustration. You can use the connectors provided by Painless, or you can use your Mustang's original gang plug.
Maximum Protection
The Painless Performance wiring harness is designed with your safety in mind. There's a main fuse box with separate fuse terminals positioned around the wiring system. The main fuse box has 12 circuits. They feed and protect the following circuits for the coil, turn signals, windshield wipers, air conditioning and heater, sound system, backup lights, electric cooling fan, switched accessory, always hot lead for clock and courtesy lights, headlights, horn and cigarette lighter (always hot), and brake lights.
Separate fuse terminals, located away from the main fuse box, protect specific areas of the electrical system. For example, there's a 10-amp instrument lamp fuse located near the main fuse box.
The Maxi-Fuse, located near the starter solenoid, protects the entire Painless Performance electrical system because it stands between battery power and the main wiring harness under the dashboard. When the 50-amp Maxi-Fuse blows, all electrical power from the battery is cut off. Think of the Maxi-Fuse as double protection, meaning there are two fuses for every circuit. Each circuit has a primary fuse at the main fuse box under the dashboard. The secondary Maxi-Fuse provides a comfortable redundancy against short circuits and fire. This feature would come in handy should a short circuit develop between the battery and main wiring harness.
This 10-amp fuse, located...
This 10-amp fuse, located near the main fuse box, is for the instrument lamps.
This is the Maxi-Fuse, which...
This is the Maxi-Fuse, which sits protected in a plastic cover at the starter solenoid. Power through the 10-gauge red wire comes from the battery's positive cable at the starter solenoid. Power enters the main wiring harness here. Removing or blowing this fuse completely disables your Mustang's electrical system.
Don't Be Rubbed The Wrong Way
One of the biggest mistakes we see in our travels is vulnerable wiring. A wire's insulation isn't enough protection against chafing, which happens when wires rub against hard surfaces. When bare wires touch steel surfaces, nasty short circuits can develop, potentially causing blown fuses or even fires. Your best path to protection is plenty of protection around the wiring. Use rubber grommets where wiring passes through steel bulkheads, and wrap your wiring in that ribbed plastic anti-chaf. These two practices, plus the use of heat-shrink, will keep your electrical system safe.