Help Center · Wiring
You just got your new horn kit up and running and you want to set it up on the upfitter switches. No idea where to start? Don’t worry — we’ve got you covered.
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.
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).
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:
The Upfitter Switches are operational when the ignition key is in the “RUN” position only. 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).
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 # | Rating |
|---|---|---|---|---|
| Aux 1 | CAC05 | Yellow | F94 | 25A |
| Aux 2 | CAC06 | Green/Brown | F95 | 25A |
| Aux 3 | CAC07 | Violet/Green | F9 | 10A |
| Aux 4 | CAC08 | Brown | F2 | 15A |
To find the wires:
Surprisingly, this is the easiest part of the process. Once you have decided on an upfitter switch to use, you may route the output lead from the desired switch out to one wire on our solenoid valve. The opposite lead from our valve can be run to the frame of the vehicle as a ground point. This will complete the circuit, and your horns will honk once the switch is flipped on.
If you are looking to use the upfitter switch to turn the train horns on and off at the steering wheel, please see our article here.
Diagnose a compressor that will not start or will not shut off — usually wiring, a blown fuse, or a failed pressure switch.
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