American Autowire Complete Wiring Harness Classic Update Kit 1965-1966

American Autowire:
81% of 100


  • Complete Wiring System
  • Gauge Cluster Easily Wired In
  • Complete Wiring For All Lights
  • All Required Hardware Supplied
MSRP $859.00
You save 10%

American Autowire Complete Wiring Harness Classic Update Kit for 1965-1966 Mustangs.

The Classic Update Series is a complete wiring system in a box, giving you everything you need to modernize your classic Mustang's wiring system. Allows for most aftermarket accessories such as: gauge packages, heat and air conditioning systems, power windows, etc.

American Autowire's 510125 Classic Update Kit's instrument cluster wiring is designed with a separate "cluster harness disconnect" system for easy service and assembly. The best aspect of the disconnect system is that any gauge cluster package can be easily and neatly wired in. This includes JME ENTERPRISES, AUTOMETER, CLASSIC INSTRUMENTS, DAKOTA DIGITAL, STEWART WARNER, and VDO just to name a few.

Features and Benefits:
Dash and Main:
- A Bussman fuse box assembly and enclosed case mount in the LH door pillar area. Detailed photos of the installed unit are included in the instructions. Mounting bracket, hardware and a mounting template are included.
- Disconnects have been added for the engine and F/L wiring. They plug in under the dash and go out through grommets in the firewall.
- Can now be used with cars that have Factory Ford underdash A/C.
- Turn signal connector is for 1969-76 style GM columns. We provide the mating connector and terminals for the customer to adapt to their switch if using a stock Ford column. Corrected and updated tables demonstrate the proper wiring configurations.
- 12v switched and 12V battery radio feeds are included.
- Correct Ford headlight switch and connector.
- Connection to original Ford style plug-n-play wiper harnesses. Addresses the different wiper harnesses available along with detailed drawings and how to tie them into the dash harness (harnesses are no included with kit, but are available from most all Mustang parts vendors). Instructions for connecting a stock wiper/washer pump are included.
- Correct Ford ignition switch and connector.
- Complete detailed factory heater and heater resistor harness drawings, wires, and connectors included.
- Complete detailed neutral safety and back up lamp switch leads with disconnect drawings, wires, and connectors included.
- Console dash connections included that will plug directly into the factory console harness (not included).
- Detailed fog lamp switch connections and drawing are included eliminating previous questions about the stock third wire.
- Electric fan trigger wire is included in this kit.
- Complete dash cluster disconnect now included along with electric speedo wiring.
- Typical left and right courtesy lamp housings are provided.
- Cigar lighter connection is included.
- Relay and connections that control headlights, fog lights and horn are included.
- Glove box lamp connection is included.

Rear Body:
- Original 90 degree molded tail lamp socket connectors are included.
- Will accommodate aftermarket tail lamp socket connections.
- Original bullet style back up lamp terminals and rubber sleeves are included.
- Original fuel tank sender connection lead with the pass-through floor grommet is included.
- Feed wire and mating terminals to original style dome and sail panels lamps are included.
- Feed wire and mating terminal to original style trunk lamp is included.
- Original style mating terminal to accommodate tag lamp is provided.
- Third brake light wiring also provided in this kit.

New Gauge Cluster:
- Original light sockets, ring terminals and connectors to connect to a stock cluster are included.
- Includes feed to optional stock instrument cluster mounted clock.
- Includes aftermarket tach wiring.
- Just as with other similar Ford kits, this kit will not support the use of a factory tach (which has the ignition source routed through the tach assembly).
- Aftermarket gauge wiring terminals and instructions are included.

New Engine Harness:
- Complete engine wiring leads out to engine compartment includes: oil pressure, temp, electric choke, tach, 12v ignition.
- Supports a 1-wire alternator and also includes an exciter wire for use with other regulator style alternators.
- 6 gauge alternator charge wire along with (2) mega-fuses to protect the alternator and main battery feed to engine/dash harnesses.

New Front Light Harness:
- Aftermarket 2 post Ford type late model brake warning molded connector is included in this kit. Directions for connection are included.
- Complete wiring, terminals and connectors to connect to the stock parking lamp pigtails to create a disconnect system. Detailed instructions are included.
- Complete wiring, terminals and connectors to connect to the stock headlights. Relay protected for use with halogen lamps.
- Complete wiring, terminals and connectors to connect to single or dual horns.

Optional Extra-Cost Harness Kits:
- An extra cost optional 4-way hazard flasher kit is available.

Rear body harness assembly plugs into the main harness behind the left hand kick panel for easy accessibility and allows for original or custom routing.

*American Autowire recommends this kit for MODIFIED original vehicles, not OEM restoration projects.
*Does NOT support ammeters.

California Residents: Proposition 65 Warning

Installation Difficulty


Advanced skill is required for this installation.

Installation Videos

Video Transcript

When we ask our customers what the most intimidating part of working on their classic Mustang is, the answer we usually get is wiring. Original wiring is often frayed and brittle, plus you never know how many times in the past it's been cut or messed with. All it takes is one bad wire or one bad ground to take your Mustang off the road. If you're looking for originality, we carry a complete selection of replacement harnesses, but if you're looking for a modern harness flexible enough to be used with your custom build, check out the harnesses from American Autowire.

This kit is part of their classic update series for the '64 through '70 Mustangs. It allows you to replace your harness, while also upgrading to modern accessories. Let's take a closer look at what's included in the kit. The first thing you see when you open this box is going to be this stop page. This page isn't designed to intimidate you from the installation, it's more to tell you what the harness can and cannot do. The harness is designed to work with a modified car and so will not work with some stock components.

For example, it does require a one-wire alternator. All of the wiring for the one wire alternator is included. This will bypass your factory ammeter gauge, which is a safety concern when running a higher output alternator. You also have to have your tach modified to work with a negative feed. The original positive feed tachs will not work with aftermarket ignition systems and can also cause problems.

Instead of your typical installation manual, American Autowire provides eight pages of high quality color diagrams, as well as mounting templates for your kit. Once you open the box and all the bags up this is what you have in the kit. It can look a little intimidating at first. American Autowire does everything they can to make it that you can do it yourself. All your wires are labeled so not only do you have the color diagrams, each individual wire has a label on it stating where it goes.

Your fuse box is also completely labeled, as well as a bank of relays to keep all the relays in the same location and original style connectors whenever possible. The rear body harness is removable making that easier to install as well. The kit includes a new headlight switch, as well as a new dimmer switch. This kit here is specific to the '70. It allows you to relocate the wires since the '70 has the ignition in the column as opposed to on the dashboard.

This kit here is for your gauges. It allows you to wire up aftermarket or factory gauges, as well as make them removable. They also include all the relays and fuses, grommets, terminals, as well as a practice kit to make sure you're doing the terminals right before you put the harness in the car.

Taking a closer look at the fuse box you're going to see your flasher, your battery, your normal fuses. There's also additional fuses for fog lights, power windows, gauges, AC and heat, as well as accessories. That makes this very flexible for adding modifications to your car.

Installing a harness like this may not be for everyone. If you take your time and follow the instructions, this classic update harness from American Autowire is an excellent choice for your resto mod.

Vehicle Fitment

This product will fit the following Mustang years:

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