F 250 2WD Super Duty V8-5.4L (2008)
upfitter relay box, closing that relay. Voltage is supplied to the switched side of the upfitter relay circuits from the battery junction box (BJB) for relays
No. 1 and No. 2; and from the SJB for relays No. 3 and No. 4. When the relay closes, voltage is supplied through the relay to the output circuits (and to
the blunt cut ends) located under the LH side of the instrument panel. The output circuits (at the blunt cut ends) supply voltage to the installed
accessories that have been connected to the upfitter relay box.
Inspection and Verification
INSPECTION AND VERIFICATION
1. Verify the customer concern.
2. Visually inspect for obvious signs of electrical damage.
VISUAL INSPECTION CHART
Electrical
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BJB fuse(s):
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7 (30A)
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8 (30A)
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SJB fuse(s):
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14 (10A)
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16 (15A)
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42 (10A)
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Upfitter relay No. 1
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Upfitter relay No. 2
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Upfitter relay No. 3
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Upfitter relay No. 4
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Upfitter relay box
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Upfitter relay switch(es)
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Wiring, terminals or connectors
3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
4. If the cause is not visually evident, verify the symptom and GO to Symptom Chart. See: Symptom Related Diagnostic Procedures/Upfitter Relay
Box