Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Auxiliary Switches
Customer Access (Upfitter) System
The auxiliary switch option package adds six switches to the overhead console. The switches are used by an upfitter to control relays for switching customer installed accessories. Each auxiliary switch has an indicator that illuminates when the switch is in the ON position. When the ignition is in the RUN or START state, the 6 auxiliary switches enable its corresponding upfitter relay in the upfitter relay box.
Upfitter relay box fuse F4 can be put into one of two positions. In Position A , auxiliary switch 5 and 6, operate with the ignition in RUN or START. In Position C , auxiliary switch 5 and 6 operate hot at all times.
Refer to Customer Access for schematic and connector information.
For accurate diagnostics of customer (upfitter) installed devices, it will be necessary to refer to the upfitter literature for information.
For more information, refer to the Owner's Literature and www.fleet.ford.com for truck body builder advisory service bulletins.
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Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.