Ford F-150 Owner's Manual page 326

Driving
The ELD is affected by the following conditions:
• The ELD will not engage if the vehicle speed is above 20 mph
(30 km/h) in 4x2, 4x4 Auto, or 4x4 High modes.
• The ELD will not engage if the vehicle speed is above or 56 mph
(90 km/h) in 4X4 Low.
• The ELD will not engage if the accelerator pedal is pressed beyond
50% during an engagement attempt
• In 4x2, 4x4 Auto, and 4x4 High modes, the ELD will automatically
disengage at speeds above 25 mph (40 km/h) and will automatically
reengage at speeds below 18 mph (30 km/h).
• In 4L (4X4 low), the ELD will automatically disengage at speeds above
62 mph (100 km/h) and will automatically reengage at speeds below
56 mph (90 km/h).
• The AdvanceTrac system has the ability to take over control of the
ELD and disable it during driving maneuvers when necessary.
If the required conditions for ELD activation are not met when the
switch is actuated, the instrument cluster will display the appropriate
information guiding the driver through the proper ELD activation
process.
Note: The ELD is designed for off-road use only and is not intended for
use on dry pavement. Using the ELD on dry pavement will result in
increased tire wear, noise and vibration.
Electronic locking differential (ELD) indicator lights
This light will be continuously
displayed in the cluster when the
ELD is active.
The indicator will turn off if the ELD automatically disengages because
the ELD threshold speeds are exceeded and will turn back on when the
ELD automatically reengages when the ELD threshold speeds are not
exceeded.
CHECK LOCKING DIFFERENTIAL– Displays when an ELD fault is
present
326
2012 F-150 (f12)
Owners Guide, 2nd Printing
USA (fus)