Jim Smart
May 1, 2003

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.

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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.

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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.