The lift axle(s) automatically lower when the vehicle is loaded. The control button is then used to raise
the lift axle when the vehicle is unloaded. When the vehicle is unloaded, the control button can be pull
out to bring the axle(s) down manually.
NOTE: To determine the desired Ps1 pressure, connect gauge to air spring line and load the vehicle as
desired for lowering the axle. The Ps1 pressure can be adjusted to the desired pressure.
Functional Check for Valve
1. Connect gauge and regulator to port 11
2. Connect pressure gauge to test port (Metric M16x1.5 threaded fitting).
3. Verify current Ps1 setting by setting the regulated pressure into the 11 port to 80 PSI.
4. Watch for the point on the test port gauge that the valve exhausts and triggers the
lowering of the axle(s).
5. Relieve pressure from test port.
The ILAS-III Manual is factory set at 62 PSI for Ps1. It is important when making an adjustment to the
Ps1 setting that the adjustment is made from a higher Ps1 setting to a lower Ps1 Setting. If this is not
followed then the Ps1 will be triggered before the adjustment can be made. The Ps1 can be set between
44 and 76 PSI.
Setting the Control Pressure Ps1
1. Set the desired pressure for lowering the lift axles using the regulator in port 11.
2. Verify that the control button is pressed in for automatic control of the lift axle.
3. Remove the yellow cap on the tube. Using the adjustment wrench (904, 053, 001), turn in
the nut until it stops. DO NOT TORQUE!
4. Allow the pressure to equalize at the test port gauge to that of the regulated pressure gauge.
Once equalized slowly back out (turn to the left) the Ps1 adjustment nut using the adjustment
wrench (904 053 001). When the valve exhausts stop adjustment, the valve has been set.
5. Verify that valve has been set correctly by repeating steps 1-5 of the functional check.
6. Enter the current Ps1 setting on the valve or in an area visible from the lift axle(s). Replace
the protective cap.
Figure 1
Figure 2
Functional Check for Valve
1. Connect gauge and regulator to port 11
2. Connect pressure gauge to test port (Metric M16x1.5 threaded fitting).
3. Verify current Ps1 setting by setting the regulated pressure into the 11 port to 80 PSI.
4. Watch for the point on the test port gauge that the valve exhausts and triggers
the lowering of the axle(s).
5. With Ps1 triggered regulated the port 11 pressure down to 10 PSI.
6. Watch for the point on the test port gauge that the valve exhausts and triggers
the raising of the axle(s).
7. Relieve pressure from test port.
The ILAS III Automatic is factory set at 62 PSI for Ps1. It is important when making an adjustment to the
Ps1 setting that the adjustment is made from a higher Ps1 setting to a lower Ps1 Setting. If this is not
followed then the Ps1 will be triggered before the adjustment can be made. Ps1 can be set between 44
and 76 PSI.
Setting the Control Pressure Ps1
1. Set the desired pressure for lowering the lift axles using the regulator in port 11.
2. Remove the yellow cap on the tube. Using the adjustment wrench (904, 053, 001), turn in
the nut until it stops. DO NOT TORQUE!
3. Allow the pressure to equalize at the test port gauge to that of the regulated pressure gauge. Once
equalized slowly back out (turn to the left)the Ps1 adjustment nut using the adjustment wrench
(904 053 001). When the valve exhausts stop adjustment, the valve has been set.
4. Verify that valve has been set correctly by repeating steps 1-5 of the functional check.
The ILAS III Automatic is factory set at 20 PSI for Ps2. In order to make an adjustment to Ps2, Ps1 must
be triggered first. It is important when making an adjustment to the Ps2 setting that the adjustment
is made from a lower Ps2 setting to a higher Ps2 Setting. If this is not followed the Ps2 will trigger
before the adjustment can be made. The Ps2 has an adjustment range of 10 to 45 PSI. This is
dependent on the Ps1 setting. See Figure 5 for adjustable range.
Setting the Control Pressure Ps2
1. Remove red cap, with fingers back out white nut until the face of the nut is at the end of the
threads. DO NOT REMOVE WHITE NUT FROM STUD!
2. Ps1 must be triggered before setting Ps2. Set regulated pressure in port 11 to 80 PSI, allow
test port to equalize with port 11 pressure.
3. Once equalized, regulate the pressure in port 11 down to the desired Ps2 setting. Allow the
test port gauge to equalize.
4. Turn in white nut (turn to the right) until valve activates. The Ps2 has now been set.
5. Verify that valve has been set correctly by repeating steps 1-7 of the functional check
above. slight adjustment may be needed to precisely set Ps1 and Ps2 as an adjustment to
one can affect the adjustment of the other.
6. Replace protective caps. Enter the current Ps2 and 2 settings on the valve or in an area
visible from the lift axle(s).
The operation of the lift axle is fully automatic based on the load applied to the vehicle. The lift axle can
be automatically lowered after the predefined control pressure, Ps1, has been reached. Likewise, the lift
axle will automatically lift when the second predefined control pressure, Ps2, has been reached. Control
pressures can be set to specific vehicle loads.
Installation Instructions for the 90555293 (Manual Lift)
Installation Instructions for the 90555288 (Fully Automatic)
