Overview
You just got your new horn kit up and running and you want to set it up on the up-fitter switches. No ideas where to start? Don't worry, we've got you covered.
The Switches
Chances are that if you are reading this article, you are already familiar with these switches and the wires that connect to them. If not, check out the quick guide below to find these switches on your vehicle.
If you've already figured out where the leads are, go ahead and skip to the bottom of this article.
2005-2007 Ford Super Duty Upfitter Switches:
The Ford Upfitter Switches are optional instrument panel mount switches (Option Code 66S) that control passenger-side mounted relays. These relays power four blunt cut wires that can be found beneath the steering column and behind the passenger compartment fuse panel also called the Central Junction Box (CJB). The wires are part of the harness connected to the “K” connector (C270K) on the back of the CJB. The four wires are as follows:
| Switches | Circuit | Color | Fuse |
| Aux 1 | 1936 | Orange/Light Green | 30 Amp |
| Aux 2 | 1933 | Orange | 30 Amp |
| Aux 3 | 1934 | Orange/Yellow | 10 Amp |
| Aux 4 | 1935 | Orange/Light Blue | 10 Amp |
The Upfitter Switches are operational when the ignition key is in the run position. The Upfitter Switches cannot be utilized in any other operational mode. The power to the switches is relay controlled and was designed to operate in the “run” mode to reduce the possibility of draining the battery(ies).
2008-2010 Ford Super Duty Upfitter Switches:
The Ford Upfitter Switches are optional instrument panel mount switches (Option Code 66S) that control passenger side mounted relays. These relays power four blunt cut wires that are taped on a harness near the relay pack that can be found beneath the instrument panel and to the left of the steering column. The four blunt cut wires are as follows:
| Switches | Circuit | Color | Fuse |
| Aux 1 | CAC05 | Yellow | 30 Amp |
| Aux 2 | CAC06 | Green/Brown | 30 Amp |
| Aux 3 | CAC07 | Violet/Green | 10 Amp |
| Aux 4 | CAC08 | Brown | 15 Amp |
How to locate the leads for these switches:
1. Remove the trim cover below the steering column.
2. Locate the relay pack beneath the instrument panel and to the left of the steering column.
3. Locate the four blunt cut wires with shrink wrap on the harness near the relay pack.