F 450 2WD Super Duty V8-6.0L DSL Turbo VIN P (2006)
I1-I3
I4
Normal Operation
The instrument cluster monitors the headlamp switch status on circuit 402 (OG/LG) to determine if the courtesy lamps are requested. Based on the
headlamp switch status, the instrument cluster then energizes the interior lamp relay. When the relay is energized, voltage is supplied to the interior
lamps through circuit 53 (BK/LB).
Possible Causes
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Circuit 57 (BK) open
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Circuit 402 (OG/LG) open
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Headlamp switch