Boss Snowplow MSC08042C Owner's Manual page 86

Troubleshooting Guide
PROBLEM
2. Pump continues to run with
switch in neutral.
DIAGNOSTIC CHECK
Test power to the controller
by checking voltage between
black wire and ground at the
white 9-pin connector.
Disconnect controller,
ignition ON.
87
RESULT
If NO voltage is present,
power from relay has become
disconnected. If voltage is
present check wiring and
controller switches.
If pump continues to run,
solenoid has failed in the
closed position. Quickly
remove power to the pump by
disconnecting the
power/ground cables to the
plow. Replace solenoid.
If pump stops running, check
wiring of controller for short
between black and white/black
wire in controller, or failed
switch.