Page 155 of 378
Trailer Air Supply and Parking Brake Modular Controls
(If Equipped)
The trailer air supply valve delivers
air to the trailer supply and
automatically pops out, shutting off
the trailer supply, if pressure
decreases to approximately 35 psi
(249 kPa).
The parking brake controls the
spring brakes on the tractor. When
the knob is pulled out, it causes the
trailer supply valve to pop out,
applying both the tractor and trailer
parking brakes. The trailer brakes
may be independently released by
pushing only the trailer air supply
valve in.
Initial Charge
With the air system completely discharged, both knobs (A and B) are
out. When the air pressure reaches 70 psi (483 kPa), the trailer air
supply (A – red knob) may be pushed in and should stay in, charging the
trailer air system and releasing the trailer brakes.
B
AB
A
154Brakes
2013 F-650/750(f67)
Owners Guide gf, 2nd Printing, March 2013
USA(fus)
Page 156 of 378
The parking brake (B – yellow knob) can now be pushed in and supply
air to the tractor spring brakes, releasing them.
Normal Driving Position
With both knobs pushed in, air is supplied to both trailer and tractor
spring brakes and all brakes are released.
B
A
B
A
Brakes155
2013 F-650/750(f67)
Owners Guide gf, 2nd Printing, March 2013
USA(fus)
Page 157 of 378
System Park
With both knobs pushed in (normal driving position), the parking brakes
for both the tractor and trailer can be applied by pulling the parking
brake knob (B) out, exhausting air from the tractor spring brakes,
simultaneously causing the trailer air supply valve to pop out, applying
the trailer brakes.
Trailer Charge
If both knobs are out, and you want to recharge the trailer while leaving
the tractor spring brakes applied, the trailer air supply (A) can be
pushed in to recharge the trailer air supply line. This mode may also be
used to park a combination vehicle with tractor spring brakes.
B
AB
AB
A
B
AB
A
156Brakes
2013 F-650/750(f67)
Owners Guide gf, 2nd Printing, March 2013
USA(fus)
Page 158 of 378

Automatic Application
If both knobs are pushed in and the brake system air pressure is reduced
to approximately 35 psi (249 kPa), the trailer air supply (A) knob
automatically pops out applying the emergency or parking brakes on the
trailer. If the trailer air supply (A) knob is manually held in and the air
pressure is reduced to approximately 30 psi (207 kPa), a tripper piston
within the valve moves, exhausting the trailer air supply, applying the
trailer brakes. Further reduction of air pressure, while holding the trailer
air supply knob in, causes the parking brake knob to pop out at 25 psi
(172 kPa).
Actuation of Trailer Park (Emergency) or Tractor Bobtail Position
To actuate the trailer brakes only, pull out the trailer air supply knob
(A). The trailer brakes are now applied whether emergency or spring
brakes are used on the trailer.
This mode is also used when the tractor or truck with trailer is used
during bobtail operation.
B
A
B
A
Brakes157
2013 F-650/750(f67)
Owners Guide gf, 2nd Printing, March 2013
USA(fus)
Page 172 of 378

AIR SUSPENSION (IF EQUIPPED)
Note:
The vehicle must not be operated without air in the suspension
springs. Operating the vehicle without air in the suspension springs damages
the suspension, degrades ride performance and may cause property damage.
The air suspension system automatically adjusts to different loads to
maintain a constant frame height, allows for ease of vehicle loading and
provides improved vehicle ride and increased driver comfort.
Air Suspension Dump Switch
Note:The suspension dumps air when the ignition is in the accessory or
on position, but fills only when the ignition is in the on position.
The system is controlled by a switch
located in the overhead switch
pack. It operates only when the
ignition is in the accessory or on
position and the air tanks have
sufficient pressure to fill the air
springs. When the ignition is turned
off, the suspension remains in
whatever state it was last set.
Pressing the lower portion of the switch exhausts air from the air
springs, lowering the frame for loading. Pressing the upper portion of the
switch fills the air springs so the vehicle remains at normal ride height.
System Indicator Light
The air suspension indicator light illuminates when the switch
has been activated to release air pressure in the rear air shocks.
Never drive the vehicle when the warning lamp is illuminated
and there is low (or no) air pressure in the shocks.
Connecting and Disconnecting a Trailer with Air Suspension and
Air Suspension Dump Switch
When connecting to a trailer:
•Press the lower portion of the switch to exhaust air from the air
suspension system.
•Press the upper portion of the switch, then raise the landing gear
after making the connection to the trailer.
When disconnecting the trailer:
•Lower the landing gear, then press the lower portion of the switch.
•Disconnect the brake hoses, trailer-side and rear light connectors,
then pull the release lever on the fifth-wheel.
CK
SUSP
Driving Aids171
2013 F-650/750(f67)
Owners Guide gf, 2nd Printing, March 2013
USA(fus)
Page 173 of 378

The upper portion of the switch must be pressed before operating with a
trailer or operating in the bobtail mode.
Suspension Conversions
WARNING:When operating a loaded vehicle, the driver must
keep all adjustable axles on the ground at all times, supporting
their share of the vehicle’s load. Failure to do so can overload other
axles, tires, wheels, springs, steering components, brakes and frames,
resulting in early component failure, loss of vehicle control, possible
property damage and personal injury.
It is not recommended, or approved, that suspension conversions be
performed. However, it is understood that, on occasion, aftermarket
add-on suspensions are installed by others on the truck chassis which
allow operator control for weight transfer from other axles (i.e., air lift
axles).
UPFITTER CONTROLS (IF EQUIPPED)
The upfitter option package
provides four switches, mounted in
the center of the instrument panel.
These switches are always on
whether the engine is running or
not. Make sure you put the switches
in the off position to avoid draining
the battery when the vehicle is not
being used. It is recommended that the engine remain running to
maintain battery charge when using the upfitter switches for extended
duration or higher current draws. (This is even more important for
vehicles with a diesel engine since the glow plugs are also draining
battery power when the ignition key is in the on position.)
Each switch provides 10 amps of electrical battery power for a variety of
personal or commercial uses.
There is also a relay box located on the passenger side end of the
instrument panel. See your authorized dealer for service.
Switch access location is in a connector located in the engine
compartment. More detailed information can be found at
https://www.fleet.ford.com/truck/bbas/.
AUX 1
AUX 2
AUX 3
AUX 4
172Driving Aids
2013 F-650/750(f67)
Owners Guide gf, 2nd Printing, March 2013
USA(fus)
Page 176 of 378

TOWING A TRAILER
WARNING:Do not exceed the GVWR or the GAWR specified on
the certification label.
WARNING:Towing trailers beyond the maximum recommended
gross trailer weight exceeds the limit of the vehicle and could
result in engine damage, transmission damage, structural damage, loss
of vehicle control, vehicle rollover and personal injury.
Your vehicle’s load capacity is designated by weight, not by volume, so
you cannot necessarily use all available space when loading a vehicle.
Second-unit bodies are not included in maximum trailer weight ratings.
The weight of the additional body must be subtracted from the maximum
trailer weight.
Towing a trailer places an additional load on your vehicle’s engine,
transmission, axle, brakes, tires and suspension. Inspect these
components periodically during, and after, any towing operation.
Load Placement
To help minimize how trailer movement affects the vehicle when driving:
•Load the heaviest items closest to the trailer floor.
•Load the heaviest items so they are centered between the left and
right side trailer tires.
•Load the heaviest items above the trailer axles or just slightly forward
toward the trailer tongue. Do not allow the final trailer tongue weight
to go above or below 10–15% of the loaded trailer weight.
RECOMMENDED TOWING WEIGHTS
Model Maximum
GVWR - lb (kg)Maximum
GCWR
F-650 Pro-Loader (Kick-Up
Frame)20500–26000
(9299–11792)
*
F-650 Pro-Loader (Straight
Frame)/F-650 Straight Frame20500–29000
(9299–13154)*
F-750 25999–37000
(11793–16783)*
Towing175
2013 F-650/750(f67)
Owners Guide gf, 2nd Printing, March 2013
USA(fus)
Page 177 of 378

*Specific GCWR and maximum trailer weight applicable to a given
F–650/750 model is dependent on many variables including transmission
capability. Check with your sales consultant for the exact rating on your
vehicle.
ESSENTIAL TOWING CHECKS
Service your vehicle more frequently if you tow a trailer. See your
scheduled maintenance information.
For load specification terms found on the Tire Label and Safety
Compliance Certification Label and for instructions on calculating your
vehicle’s load, seeLoad limitin theLoad Carryingchapter.
Hitches
Do not use a hitch that either clamps onto the bumper or attaches to the
axle.
Distribute the trailer load so 10-15% of the total trailer weight is on the
tongue.
Safety Chains
Note:Do not attach safety chains to the bumper.
Always connect the trailer’s safety chains to the frame or hook retainers
of your vehicle hitch.
To connect the trailer’s safety chains, cross the chains under the trailer
tongue and allow enough slack for turning tight corners. Do not allow the
chains to drag on the ground.
Trailer Brakes
WARNING:Do not connect a trailer’s hydraulic brake system
directly to your vehicle’s brake system. Your vehicle may not have
enough braking power and your chances of having a crash greatly
increase.
Electric brakes and manual, automatic or surge-type trailer brakes are
safe if installed properly and adjusted to the manufacturer’s
specifications. The trailer brakes must meet local and federal regulations.
The braking system of the tow vehicle is rated for operation at
the GVWR not GCWR.
176Towing
2013 F-650/750(f67)
Owners Guide gf, 2nd Printing, March 2013
USA(fus)