2005-2007 Ford Super Duty Upfitter Switches:
The Ford Upfitter Switches are optional instrument panel mount switches (Option Code 66S) (see
Photo 1) 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 (see Attachment II & III). The four wires are as follows
(see Photo 3):
| 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 |
To find the wires:
1. Remove the fuse panel trim cover below the steering column.
2. Remove the four fasteners holding the CJB.
3. Lower the CJB without disconnecting any connectors.
4. Locate connector “K” (see Attachment II & III) on the back of the CJB and the harness
connected to it.
5. Locate the four blunt cut wires with shrink wrap on the harness connected to the “K” connector
(See Photo
Operating Procedure:
The Upfitter Switches are operational when the ignition key is in the run position (see Attachment
I). 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).
