American Autowire 66-77 Bronco Harness

Item #: 6050W
Classic Update Kits give you one of the most complete kits on the market to "Make Wiring THAT Easy". This kit is designed specifically for the 1966-77 Ford Bronco and boasts 14 features making it the most complete system of its type in the industry.

This item will receive FREE SHIPPING to anywhere in the 48 contiguous states. The shipping charge for this item will have already been deducted from the shipping charge shown in checkout.
Customers outside of the 48 contiguous states will be emailed the shipping charges for approval prior to shipping.

PLEASE BE AWARE: Shipping is free to you unless you return the product. If you decide to return the product you are responsible for shipping back to WILD HORSES. The original shipping cost incurred by WILD HORSES will be deducted from any refund. Restocking fees may also apply.


Classic Update Kits give you one of the most complete kits on the market to "Make Wiring THAT Easy". They are designed for specific year, make, and model configurations. The 1966-77 Ford Bronco Kit is no exception. The kit boasts 14 features making it the most complete system of its type in the industry including:
  • A replacement headlight switch with internal 25-amp circuit breaker, adjustable length shaft, and custom knob.
  • Standard turn signal flasher, hazard flasher, and horn relay mounted on harness.
  • NEW compact ATO-Style fuse panel that is fully encased in a closed box assembly with coverlid and mounts inside the glove box (mounting hardware included). The fuse coverlid is labeled on the inside identifying all circuits by description and their respective fuse ratings. All high amperage output circuits incorporate the same superior spring steel reinforced terminals that are used in our Highway Series kits.
  • Harness is laid out and formed to allow for nearly all after market accessories such as; gauge packages, heat and air conditioning systems, etc.
  • Many original switch connector bodies - an American Autowire exclusive feature.
  • Steering column connectors can plug directly into most aftermarket steering columns or stock 1966-77 Ford columns using the adapter and terminals included in the kit.
  • Separate under dash courtesy lamp assemblies are also included for use along with your original dome/interior lighting feeds.
  • Instrument Cluster wiring is designed with a "cluster harness disconnect" system for easy service and assembly. Original terminals and connectors (another American Autowire exclusive) are provided for stock cluster connections. The system will also connect into most popular aftermarket gauges such as DAKOTA DIGITAL, CLASSIC INSTRUMENTS, AUTOMETER, VDO, and others.
  • Rear body harness assembly plugs into the main harness at the left kick panel location and our longer leads allow for stock or custom routing of the wires. Rear body wiring includes backup light lead wires and connectors along with stop and tail light lead wires and connectors to mate into the stock Ford tail and back up lamp pigtail assemblies. A license plate lamp lead connection, as well as fuel tank sender leads and tank extensions for both single and dual tank applications are also included.
  • New floor dimmer switch is provided for ease of installation. Wire length and connection accommodate original floor mount dimmer switch.
  • Engine wiring includes feeds for coil, tach, water temperature, oil pressure, electric choke, and electric speedometer (if needed). A heavy gauge alternator feed and fusible link are also included for any typical high output 1 wire or internally regulated alternator. Connectors supplied for power and tach leads for GM style H.E.I. distributors along with various oil and temp senders. A Ford Gen III series alternator adapter is available separately.
  • Front lighting includes extra long leads that can be routed for stock or optional appearances. All head light, parking light, and directional light leads, along with a switched trigger wire for an electric fan relay (usually recommended with AC) are provided. Mating terminals and connectors are also provided for you to complete your custom installation.
  • New ignition switch with indexed connector included.
  • New windshield wiper switch with indexed connector and motor leads included (must be mated to your stock motor through your windshield frame assembly).
Please note: Classic Update Kits do not support Ammeters


This harness is intended to be used in a modified vehicle. Please read this warning thoroughly and be sure that you understand everything explained here prior to opening any of the packages included in this kit, or before attempting to install any of the components. Once this kit has been opened or a component installed, the kit is not returnable. Some early Broncos had rectangular holes in the firewall behind the engine and a small round hole in the upper driver side of the firewall. For this kit, you will need to open up the driver's side hole to 1 1/2" and you will need to make a new 1 1/2" hole on the passenger's side as well. The center rectangular hole will not be used at all and should be closed up in some way. New grommets to line these two new 1 1/2" holes have been provided for you in the 510323 grommet and parts kit.

1. This kit should typically be used in a MODIFIED application only. You will need to purchase a new plastic glove box liner assembly, WILD HORSES P/N 3420 available below, to mount the new AAW harness into your vehicle as the fuse panel mounts inside the left hand side of the glove box area where the factory dash speaker was originally located. You cannot use a stock radio speaker when using this kit without relocating the fuse panel.

2. This kit only supports the use of a higher current self-exciting 1 wire, or other style internally regulated alternator. An adapter may be necessary for certain applications. The use of a stock, low amperage alternator is seriously discouraged as they cannot handle the higher current requirements of updated ignition systems, electric fans, aftermarket A/C systems, stereo systems, air ride suspensions, and other power hungry accessories and will ultimately create performance issues with the system.

3. This kit WILL NOT support the use of a factory ammeter. All AAW kits are engineered to supply the optimum charge to the battery. To achieve this performance, we route our 8 ga. charge wire directly from the alternator output terminal to the starter solenoid. Due to the path of the charge being altered from the stock configuration, the guage can no longer see a charge vs. a discharge, so it will not work properly. When ammeters were originally used, most generator or alternator current outputs were rated at maximum of about 25-60 amps. Modified vehicles being built today typically use a 100 amp or higher output alternator. With these higher current units, ammeters, generally speaking, become a safety hazard. Ammeters are usually wired in parallel to the charging circuit, are typically unfused, and can short very easily causing a fire. A voltmeter is recommended as a good alternative.

4. This kit IS NOT set up with a resistance wire or a ballast resistor for a standard, points type ignition system. It is wired with a full 12 volt primary ignition feed that is hot in both the start and run positions. It will support HEI, MSD, other electronic ignition systems, as well as computerized Fuel Injection systems. If you wish to run a points type system, there are illustrations on the engine connection pages to do so. Extra parts that are not included in this kit will be required to complete that operation.

Watch the Video!

WARNING: This product may contain chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm.

Please consider upgrading the headlight harness. The Bronco light switch can barely handle the current needed to run stock headlights. Many have had the flickering Bronco headlight syndrome. The stock headlight switch definitely can't handle the current needed to run modern H4 bulbs. The way the Bronco is wired, the power runs from the battery into the dash, branches off a few times, then into the headlight switch. The headlights are then drawing power from this switch. What that means is after all the voltage drops, you end up with lower voltage at the headlights. The Night Lighter harness uses a relay system to put direct battery voltage (often 14.4 volts) directly to your headlights creating a brighter light.

Plug the harness in and the old light switch activates the new harness and the load bearing relays to bring power from the battery directly to the headlights. WH recommends adding the Night Lighter to any stock or after market wiring harness.

* Please make selection

* Please consider the WH wire loom kit. It includes more then enough loom for the complete Bronco harness.

* Need the deluxe grounding kit?

American Autowire 66-77 Bronco Harness
Item #: 6050W


Removing Terminals Part One
Removing Terminals Part Two
Toggle Turn Switch
Fuse Panel Kit

Product Reviews

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Oct 23, 2017  |  By Rich Moore
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American auto wire harness comes w/schematic in instructions was designed well &fit well.

Bronco harness
Jun 25, 2017  |  By Danny
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Good harness instruction jump around a little but good quality and nice fit

American Autowire Harness
Apr 3, 2017  |  By Shawn
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We installed this into my 1971 Fuel Injected Bronco. Turned out great with extra options and leads if I want to add switches in the future. The labeling on the wires was really cool. We only had a few hangups when we had repeat wires from the EFI harness (i.e. feel pump, alt charge). Instructions were good and the $$$ was worth it.

Complete re-wire kit
Dec 17, 2016  |  By Rod1026
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Great upgrade to aged wiring system

Jul 12, 2016  |  By Aaron Lewis
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Fit very well

Autowire harness
Jun 28, 2015  |  By Brian
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Installed easily and everything works great

Apr 7, 2014  |  By Brian
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worked great for my modified bronco.

Highly recommended
Feb 25, 2014  |  By J.D.
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A while lot easier to install than I thought it would be. Got all the extra wires and fuses for a highly modified EB