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2005 F-Series Super Duty Upfitter Switches
Models Affected All 2005 Model Year F-250/350/450/550.
Purpose
To utilize Ford Upfitter Switches on F-Series Super Duty trucks.
Description
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
2).
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).
If you have any questions, please contact the Ford Truck Body Builders Advisory Service as shown in the header of
this bulletin.
I think you are looking in the wrong place. In my 05, the blunt cut wires are behind the drivers side fuse block. If you remove the 4 10mm bolts holding in the fuse panel and pull that out carefully, the wires should be right there. they are labled aux 1-4. 1&2 are fused for 30 amps and 3&4 for 10 amps. The wires are also located in the engine compartment on the drivers side firewall towards the top in case you are tapping in for something on the outside of the truck.
this is a simple question but is it the case that once located, all that has to be done to utilize the upfitter power is to connect the above refenced blunt cut wires (the ones off the switches) to the appliance to be powered? In other words you need not attach the upfitter switch wire to the junction box,right? so is it the case that the the shrunk wrapped blunt cut wires (not the pass through wires) are part of a circuit that has already run through the junction box fuse panel to the switches and then back near to the junction box?
this is a simple question but is it the case that once located, all that has to be done to utilize the upfitter power is to connect the above refenced blunt cut wires (the ones off the switches) to the appliance to be powered? In other words you need not attach the upfitter switch wire to the junction box,right? so is it the case that the the shrunk wrapped blunt cut wires (not the pass through wires) are part of a circuit that has already run through the junction box fuse panel to the switches and then back near to the junction box?
Correct. They blunt cut wires are already fused and have relays. Below is a link that explains how to add them if they are not already factory installed. In my previous post I mentioned there were wires in the engine compartment by the firewall which was for the upfitter switches. These are in fact just "passthrough" wires which make it easier to get wires from inside the cab to the engine compartment without putting holes in the firewall.