Problem
Possible Cause
Corrective Action
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 2500 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 2500
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 2500 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 Lift 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.
1. The pressure line are not connected
properly.
1. Check the pressure line routing.
Connect the pressure line from the P
valve on the pump to the P valve on
the valve manifold.
The plow blade wing(s) extend prior to
raising the plow and do not retract.
2. The return line are not connected
properly.
2. Connect the return line from the R
valve on the pump to the R valve on
the valve manifold.
1. The wing-return solenoid valve is
contaminated.
1. Clean or replace the solenoid valve.
The plow blade wing(s) drift back when
extended or retract too quickly when
plowing.
2. The pressure relief valve is
contaminated.
2. Clean or replace the pressure relief
valve. Refer to an authorized BOSS
Dealer.
The plow lowers too fast.
1. Check the flow-control valve.
1. Close the flow-control valve to the
desired drop speed.
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