2003 FORD F SERIES MOTORHOME AND COMMERCIAL CHASSIS fuel pump

Fuse/Relay
LocationFuse Amp
RatingPower Distribution Box
Description
24 40A** IP battery feed (fuses #4, 10, 16)
25 50A** Ignition switch feed (IP fuses #1,
5, 7, 11, 13, 14, 17, 19, PDB fuses
#7, 9, 11)
26 60A** Ignition switch feed (IP fuses #5,
11, 17, 26, 32, 38)
27 30A** Multifunction switch (headlamps)
28 — Not used
29 60A** Power brake assist motor***
Relay 1 — DRL on/off relay
Relay 2 — Fuel pump relay
Relay 3 — Horn relay
Relay 4 — A/C system relay
Relay 5 — Blower motor relay
Relay 6 — PCM relay
Diode 1 — PCM diode
Diode 2 — Park brake diode
* Mini Fuses ** Maxi Fuses ***
Vehicles with Hydromax brake assist only
Relay module
The relay box is located by the power distribution box in front of the
radiator in the engine compartment.
The relays are coded as follows:
Relay location Description
1 Back up Lamp
2 Running Lamp
3 Not Used
4 Headlamp DRL
12 43
Roadside emergencies
44

When refueling always shut the engine off and never allow
sparks or open flames near the filler neck. Never smoke while
refueling. Fuel vapor is extremely hazardous under certain conditions.
Care should be taken to avoid inhaling excess fumes.
The flow of fuel through a fuel pump nozzle can produce static
electricity, which can cause a fire if fuel is pumped into an
ungrounded fuel container.
Use the following guidelines to avoid static build-up when filling an
ungrounded fuel container:
•Place approved fuel container on the ground.
•DO NOT fill a fuel container while it is in the vehicle (including the
cargo area).
•Keep the fuel pump nozzle in contact with the fuel container while
filling.
•DO NOT use a device that would hold the fuel pump handle in the fill
position.
Choosing the right fuel
Use only UNLEADED FUEL. The use of leaded fuel is prohibited by law
and could damage your vehicle.
Do not use fuel containing methanol. It can damage critical fuel system
components.
Your vehicle was not designed to use fuel or fuel additives with metallic
compounds, including manganese-based compounds containing MMT.
Repairs to correct the effects of using a fuel for which your vehicle was
not designed may not be covered by your warranty.
Octane recommendations
Your vehicle is designed to use
“Regular” unleaded gasoline with
pump (R+M)/2 octane rating of 87.
We do not recommend the use of
gasolines labeled as “Regular” that
are sold with octane ratings of 86 or lower in high altitude areas.
Do not be concerned if your engine sometimes knocks lightly. However, if
it knocks heavily under most driving conditions while you are using fuel
87(R+M)/2 METHOD
Maintenance and specifications
69

with the recommended octane rating, see your dealer or a qualified
service technician to prevent any engine damage.
Fuel quality
If you are experiencing starting, rough idle or hesitation driveability
problems during a cold start, try a different brand of “Regular” unleaded
gasoline. “Premium” unleaded gasoline is not recommended (particularly
in the United States) because it may cause these problems to become
more pronounced. If the problems persist, see your dealer or a qualified
service technician.
It should not be necessary to add any aftermarket products to your fuel
tank if you continue to use high quality fuel of the recommended octane
rating. Aftermarket products could cause damage to the fuel system.
Repairs to correct the effects of using an aftermarket product in your
fuel may not be covered by your warranty.
Many of the world’s automakers
issued the World-wide Fuel Charter
that recommends gasoline
specifications to provide improved
performance and emission control
system protection for your vehicle.
Gasolines that meet the World-wide
Fuel Charter should be used when
available. Ask your fuel supplier
about gasolines that meet the
World-wide Fuel Charter. In Canada,
look for fuels that display theAuto Makers’ Choice
logo.
Cleaner air
Ford endorses the use of reformulated “cleaner-burning” gasolines to
improve air quality.
Running out of fuel
Avoid running out of fuel because this situation may have an adverse
affect on powertrain components.
If you have run out of fuel:
•You may need to cycle the ignition from OFF to ON several times after
refueling, to allow the fuel system to pump the fuel from the tank to
the engine.
•Your “Service Engine Soon” indicator may come on. For more
information on the “Service Engine Soon” indicator, refer to the
Instrument clusterchapter.
Maintenance and specifications
70

amount of fuel in a full tank and a tank when the fuel gauge indicates
empty. Empty reserve is the small amount of fuel remaining in the fuel
tank after the fuel gauge indicates empty.
The amount of usable fuel in the empty reserve varies and should
not be relied upon to increase driving range. When refueling your
vehicle after the fuel gauge indicates empty, you might not be
able to refuel the full amount of the advertised capacity of the
fuel tank due to the empty reserve still present in the tank.
For consistent results when filling the fuel tank:
•Turn the engine/ignition switch to the off position prior to refueling,
an error in the reading will result if the engine is left running.
•Use the same filling rate setting (low — medium — high) each time
the tank is filled.
•Allow no more than 2 automatic click-offs when filling.
•Always use fuel with the recommended octane rating.
•Use a known quality gasoline, preferably a national brand.
•Use the same side of the same pump and have the vehicle facing the
same direction each time you fill up.
•Have the vehicle loading and distribution the same every time.
Your results will be most accurate if your filling method is consistent.
Calculating fuel economy
1. Fill the fuel tank completely and record the initial odometer reading
(in kilometers or miles).
2. Each time you fill the tank, record the amount of fuel added (in liters
or gallons).
3. After at least three to five tank fill-ups, fill the fuel tank and record
the current odometer reading.
4. Subtract your initial odometer reading from the current odometer
reading.
5. Follow one of the simple calculations in order to determine fuel
economy:
Calculation 1:Multiply liters used by 100, then divide by total
kilometers traveled.
Calculation 2:Divide total miles traveled by total gallons used.
Keep a record for at least one month and record the type of driving (city
or highway). This will provide an accurate estimate of the vehicle’s fuel
Maintenance and specifications
74

Engine block heater ...................23
Engine oil ....................................57
checking and adding ................57
dipstick ......................................57
filter, specifications ............58, 88
recommendations .....................58
refill capacities ..........................89
specifications ......................91–92
Exhaust fumes ............................23
F
Fail safe cooling ..........................66
Fluid capacities ...........................89
Fuel ..............................................67
calculating fuel economy .........73
capacity .....................................89
choosing the right fuel .............69
comparisons with EPA fuel
economy estimates ...................76
detergent in fuel .......................70
filling your vehicle
with fuel ..............................67, 73
filter, specifications ............71, 88
fuel pump shut-off switch .......36
improving fuel economy ..........73
octane rating .......................69, 92
quality ........................................70
running out of fuel ...................70
safety information relating to
automotive fuels .......................67
Fuses ............................................38
G
Gas mileage (see
Fuel economy) ............................73
Gauges .........................................11
GAWR (Gross Axle
Weight Rating) ............................31
calculating .................................32
definition ...................................31driving with a heavy load ........31
location ......................................31
GVWR (Gross Vehicle
Weight Rating) ............................31
calculating ...........................31–32
definition ...................................31
driving with a heavy load ........31
location ......................................31
H
Hazard flashers ...........................36
Headlamps ...................................14
daytime running lights .............14
flash to pass ..............................15
high beam .................................14
turning on and off ....................14
I
Ignition ...................................20, 92
Inspection/maintenance
(I/M) testing ................................77
Instrument panel
cluster ..........................................8
lighting up panel and
interior .......................................15
J
Jack ..............................................45
positioning .................................45
storage .......................................45
Jump-starting your vehicle ........48
K
Keys
positions of the ignition ...........20
L
Lamps
cargo lamps ...............................15
Index
95