How To Use Super Duty Aux Switches?

Are you wondering what you can do with the auxiliary switches on your Ford Super Duty truck, and do you want to know how to use them? You've come to the right place, for we have researched this question and have the answer for you. Let's begin.

Ford's Super Duty trucks have wires ready to be connected to an aftermarket device. Check your user manual to find out the colors of the wires that correspond to each auxiliary switch.

The user manual will also tell you the type of fuse connected to that auxiliary switch, giving you an idea of the capacity of that circuit.

This post will discuss auxiliary switches and how to connect devices to them. We will also cover related questions and offer installation tips. With that said, let's dive right into this article!

Ford Super Duty Trucks Explained

Ford F250 super duty truck at sunset

Ford's Super Duty trucks are working vehicles. These trucks are ideal for heavy-duty hauling, towing, and plowing.

Thus, it is not uncommon for Ford's Super Duty trucks to have modifications that make them more adept at their job. Though most of these modifications or accessories do not require additional power, some do.

If you plan to install additional lights or a winch, you can connect these accessories to the auxiliary switches that find in Ford's Super Duty trucks from as early as the 2005- to 2007-year models.

These early auxiliary switches are usually below the AC control of the center console. There were only four of them in these early models.

Increasing the number of auxiliary switches will make it too crowded on the center console, especially with the increase in the popularity of 2-DIN entertainment systems.

Thus, newer Super Duty trucks have their auxiliary switches at the top center console.

2-DIN systems are those that use two rows on the dashboard.

Auxiliary Switches

The auxiliary switches are more popularly known as up-fitter switches.

The word "up-fitter" is an old term well-known in the trucking world but not so much elsewhere. It is unknown when it was first used. However, it combines the words "upgrading" and "outfitting."

Various aftermarket companies made up-fitter switches for older truck models. Newer Ford Super Duty trucks now offer auxiliary switches as an optional add-on.

Although auxiliary switches are an option for newer Super Duty trucks, aftermarket auxiliary switches continue to thrive.

Auxiliary switches operate with 12 volts of electrical energy from the car battery. However, many accessories require a high electrical current circuit to work.

This is where the relays come in. The auxiliary switches in Ford's Super Duty trucks include a relay. Relays are a kind of switch that uses a small current to activate a circuit that uses a large current.

The relays in Ford's Super Duty trucks use a small electromagnet. When you turn on one of the auxiliary switches, you also activate the electromagnet. This pulls one side of a lever.

Once the lever moves, the opposite end of the lever will push a conductive plate to complete the high-current circuit and allows electrical energy to pass through.

How Do You Connect A Fog Light To An Auxiliary Switch?

Ford Mondeo, Car engine close-up. Internal combustion engine, car parts, deteyling. - How To Use Super Duty Aux Switches?

The auxiliary switches are on the overhead center console of your Super Duty truck. All the auxiliary switches will only work if the ignition key is in the "On" position.

It doesn't matter if the engine is running or not.

However, it is a good idea to run the engine and leave it idle to ensure the battery will not run out of charge.

Check Accessory

  1. Check the power or current rating of your fog light. This is in amperes or amps.
    • When you install any other electrical accessory, you need to check the power rating.
    • The power rating of the accessory must be lower or equal to the power rating of the switch.
    • One or two auxiliary switches always have a higher power or current rating than the rest.
  1. Check the user manual for the power rating of the aux switches.
  2. Match the aux switches' power rating to the accessory you will install.
  3. After picking the auxiliary switch to use for your fog light or accessory, check the user manual for the color of wires that connect to that auxiliary switch.

Prepare Your Vehicle

Picture showing muscular car service worker repairing vehicle.

  1. Park your truck on level ground.
  2. Activate the parking brakes.
  3. Set the gear shifter to Park(P) if you have an automatic transmission or to the first gear if you have a standard transmission.
  4. Use a socket or a wrench to loosen the bolt that holds the battery's terminals.
  5. Disconnect the cables from the battery.

DEWALT Socket Set is available on Amazon through this link.

Locate The Wire Harness

Large wide cable with wires and connectors and terminals in the wiring repair shop and electricians for connecting

Make sure your truck's engine is cold enough to work on before proceeding.

  1. Open the hood of your Super Duty truck.
  2. Locate the fuse block that contains the fuses and relays for the auxiliary switches. It usually is on the front passenger side. Another place to look is close to the car battery.
    • Some year models, like 2017 to 2019, have the fuse block on the driver's side.
  1. When you find the fuse block for the auxiliary switches, locate the clips on the side that keep it in place.
  2. Loosen the clips and lift the fuse block.
  3. Under the fuse block is a bundle of wires wrapped in black tape.
    • In older models, the wires may or may not be wrapped.
  1. Unwrap the bundle of wires and look for the color of wire that you need.
    • The wires will have a label when you unwrap the bundle in newer Super Duty trucks.
    • The labels will say "Relay 1," "Relay 2," and so on. Each relay number corresponds to the auxiliary switch number.
    • There are wire color combinations for each relay that you will need to locate.
    • These labels will make it easier to locate the wire you need.
    • There will be two colors on the label for each auxiliary switch. The first color is the main color of the wire, while the second color is the line that goes along the length of the wire.

DOWELL 10-22 AWG Wire Stripper is on Amazon.

Make The Connection

The car headlight is disassembled. Car headlight repair close-up. An auto mechanic repairs the headlight of the car. The master connects the wires in the headlight.

  1. Install the fog lights where you need them to be.
  1. Identify the hot wire on the accessory.
  2. Bring the hot wire of the accessory to the engine bay.
    • You will need to connect an extension wire if the wire is not long enough.
    • When getting your extension wire, make sure it is of a gauge that can handle the electrical current that will flow through it.
    • The hot wire is usually the positive wire on the accessory.
  1. Connect the ground, the black wire, or the fog light's negative wire to the truck's frame.
    • Look for an area on the frame that has an existing wire connection.
    • Alternatively, you can look for a clear area on the frame to connect the ground of the fog light or accessory.
    • You can also look for a nearby bolt that goes to the frame of your truck. Loosen that bolt and connect the ground wire to it. Tighten the bolt once more after you're done.
    • If your fog lamp or electronic accessory is close to the battery, you can connect the ground wire to the car battery's negative terminal instead.
  1. Strip the hot wire from the fog light. Match the same length of exposed wire on the auxiliary switches.
  2. Insert a heat shrink tube into the wires.
    • Pick a heat shrink tube with the correct diameter for the wires you connect.
    • Heat shrink tubes can only shrink up to around half their original diameter.
  1. Connect the hot wire from the fog light and the wire with the right color from the auxiliary switch.
    • If you're connecting an accessory, connect the hot wire to the auxiliary switch wire with the right color.
  1. Solder the connection.
    • When soldering the wires, apply enough soldering wire to cover the small spaces between the two wires.
  1. Position the heat shrink tube between the connection of the wires.
  2. Use a heat gun to shrink the tube in place.
    • Using the heat gun, use a sweeping motion to heat the tube evenly.
    • Overheating the heat shrink tube will expose your underlying wiring.
  1. Reconnect the wires to the battery terminals. Tighten the bolts that hold them in place.
  2. Test the connection. Switch the ignition key to the "On" position.

Products You May Need

Heat Shrink Tubing is available on Amazon.

SEEKONE Heat Gun is available on Amazon.

MAIYUM Solder Wire is available on Amazon.

To Finish Up

Ford Super Duty trucks make it simple to add electronic devices to your vehicle. There are easy-to-access switches, wires, circuits, relays, and fuses that are ready for your equipment.

And while we have your attention, check out these related articles:

How To Remove A Ford Emblem From The Grille?

How To Remove Super Duty Steering Wheel?

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