Advertisement
4-4 REAR SUSPENSION
AIR FLOW (Refer to Figure 4)
The air flow in this system is controlled by
two components:
the height control valves
(bolted to the wheel wells and linked to the
control arm) and two 2-way normally closed
solenoid valves (located in the air suspension
control module) .
These electrically actuated
air valves, when closed or de,-energized, block
air flow in either direction. This
helps to
maintain proper ride height with a minimum
possibility of leak down.
When the ignition key is turned to the "ON"
or "ACCESSORY" position, these valves are
electrically energized, allowing positive air
flow in either direction (ie ., into or out of the
bellows).
The demand for air is "read" by the
height control valves, which move up and down
with the frame as ride height varies.
However, these valves will allow air into or
out of the bellows only when a change in
vehicle load causes actuation of the valve inlet
or exhaust cores.
Road bumps and irregular-
ities move the HC valves within a free travel
range, without adding or releasing compressed
air to the system.
ELECTRO-LEVEL REAR
SUSPENSION
The optional Electro-Level System provides
the ability to raise or lower the rear of the
vehicle approximately four inches from normal
ride height.
The control components and the
physical system on the vehicle are the same as
those
on
the
standard
system,
with
the
addition of four 3-way solenoid valves .
The Electro-Level Controls are mounted on
the lower dash panel to the right of the
Figure 5-Electro-Level Controls
steering wheel (figure 5). The controls consist
of three rocker switches that automatically or
manually level the vehicle .
Figure 6 is a
schematic of the Electro-Level controls.
SWITCHES
The two RAISE-LOWER switches are used as
necessary to raise or lower the rear of the
vehicle (as when parked on surface that is not
level) . Engine need not be running to operate
the system in either of these modes. However,
the ignition switch must be in the "ON" or
"ACCESSORY" position.
The
center
TRAVEL
switch
has
two
positions-
TRAVEL
HOLD
and
TRAVEL
AUTO.
TRAVEL HOLD is the switch position to be
used for normal highway driving .
This mode
allows the vehicle to maintain a designed ride
height and eliminates unnecessary operation of
the air compressor .
TRAVEL AUTO is the
position to be used to "ready" the vehicle for
highway driving after it has been parked in a
raised or lowered position. This leveling of the
vehicle will take place in the first five minutes
with the rocker switch in TRAVEL AUTO
position .
AIR FLOW (Refer to Figure 7)
The air flow in the system (to or from the
air bellows) is controlled by switch position on
the Electro-Level control panel .
When the center switch is placed in TRAVEL
AUTO, only the two-way solenoids "E" and "F"
are open, i .e., energized . If air is needed in
the system, this mode will allow air to flow
from the compressor through the height con-
trol valve and further through solenoids "A",
"C" and "E" on the left side to the bellows. On
Advertisement
