Power distribution box
The power distribution box is located in the engine compartment. The
power distribution box contains high-current fuses that protect your
vehicle’s main electrical systems from overloads.
WARNING:Always disconnect the battery before servicing high
current fuses.
WARNING:To reduce risk of electrical shock, always replace
the cover to the Power Distribution Box before reconnecting the
battery or refilling fluid reservoirs.
If the battery has been disconnected and reconnected, refer to the
Batterysection of theMaintenance and Specificationschapter.
The high-current fuses are coded as follows:
Fuse/Relay
LocationFuse Amp
RatingProtected Circuits
1 Relay Blower motor/Variable blower
control (Dual Zone Climate
Control)
2 Relay Electronic Shift-on-the-Fly
(ESOF) Lo-Hi
3 Relay Heater mirror
4 — Not used
5 30A* Trailer Brake Controller (TBC)
2009 F-250/350/450/550(f23)
Owners Guide, 1st Printing
USA(fus)
Roadside Emergencies
321
Fuse/Relay
LocationFuse Amp
RatingProtected Circuits
53 Relay PCM power bus (Fuses 68, 70,
72, 74, 76) (Diesel engine only)
54 Relay Starter solenoid
55 Relay Trailer tow park lamps
56 Relay Trailer tow battery charge
57 Relay Power Distribution Box (PDB)
bus (fuses 67, 69, 71, 73, 75, 77)
SJB Run /Start bus (Fuses 29–37,
46)
58 Relay ESOF hi-lo
59 Relay PCM power bus (Fuses 68, 70,
72, 74, 76) (Gasoline engines
only)
60 Diode One touch start (OTIS)
61 Diode A/C clutch
62 Diode Fuel pump
63 15A** Trailer tow back-up lamps
64 5A** Mirror marker lamps
65 — Not used
66 — Not used
67 — Not used
68 — Not used
69 — Not used
70 10A**Gasoline engines:A/C clutch
relay coil, Refrigerant
Containment Switch, Heated PCV
Diesel engine:A/C clutch relay
coil, Clutch switch, Fuel pump
cooler, A/C cycle pressure switch
71 5A** Fuel pump relay diode,
PCM/ECM Run/Start power
72 15A**Gasoline engines:Ignition coils
Diesel engine:Engine TCM
73 2A** Reverse Camera System (RCS)
2009 F-250/350/450/550(f23)
Owners Guide, 1st Printing
USA(fus)
Roadside Emergencies
324
