Problem
Possible Cause
Corrective Action
1. The power/ground cables or control
cables are not connected properly.
1. Connect the cables if they are not
connected.
2. The wiring on the hydraulic valve
manifold is not connected properly.
2. Refer to the wiring schematic and
connect the wiring properly.
3. The solenoid valve or valve coil has
failed.
3. Check for voltage between the lower
solenoid valve terminal on the orange
wire and ground with the vehicle
ignition switch on and the control
switch in the LOWER/FLOAT position.
If voltage is present, the lower solenoid
valve or valve coil has failed. Replace
the solenoid valve.
The plow does not lower.
4. Power from the relays is disconnected.
4. Check for voltage to the control
between the black wire and ground
at the white 9-pin control connector
of the vehicle side harness with the
vehicle ignition switch on and the plow
electrically connected to vehicle. If
voltage is not present, the power from
the ignition-on 12V+source (from the
vehicle) on the black/red wire has
become disconnected or the relay on
the plow side harness has failed. If
voltage is present, check the wiring
and control. Connect, repair, or replace
the wiring.
1. The hydraulic-fluid level is low.
1. Check the hydraulic-fluid level; refer
to the Checking the Hydraulic Fluid
section.
2. The power/ground cables or the control
cable are not connected.
2. Connect the cables.
3. The wiring on the valve block is not
connected.
3. Refer to the wiring schematic.
4. The battery is weak or needs replacing.
4. Load a test battery and replace it if
necessary.
5. The pump pressure relief valve is
less than 1200 psi, contaminated, or
damaged.
5. Check the pressure at the hydraulic
lift cylinder port of the hydraulic power
unit. If the pressure is less than 1200
psi (at the end of the lift), the hydraulic
pump motor may be defective, the
main pump pressure relief valve may
be contaminated, damaged, set lower
than 1200 psi, or the pump may be
worn. See an authorized BOSS dealer
for an adjustment or to replace the
hydraulic power unit assembly.
6. There is a leak in the hydraulic system.
6. If a hydraulic fluid leak is present at the
hydraulic hose end or fitting, tighten
the fitting. If the fluid leak is present
at the hydraulic power unit or cylinder,
a component replacement may be
necessary.
The plow does not raise or raises slowly.
7. The Raise control solenoid valve is not
operating completely.
7. Check for voltage between the raise
solenoid valve terminal on the white
wire and the ground with the vehicle
ignition switch in the on position and
the control switch in the Raise position.
If voltage is present, the raise solenoid
valve or the valve coil has failed.
Replace the solenoid valve.
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