Let's start with basics. What Valve does what....

Raise - Motor & B Valve (Red Wire)
Lower - A Valve (Black Wire)
Right Angle - Motor & C Valve (Green Wire)
Left Angle Motor (White Wire)

The fluid leaves the Gear Pump and goes through the high pressure filter
(the higher one on the right) and then to the B Valve (closed) and then through
the C Valve (closed) and out to the passenger side PA Ram making the plow go
left. So left is "default" in that there is no Valve to go left.

So to raise, the fluid leaves the Gear Pump and goes through the high pressure filter and
to the B Valve which should be open (Coil has magnetism), diverting ALL the fluid into the lift cylinder, raising the plow.
IF the B Valve did not open all the way, the remaining fluid and pressure
would continue on through the C Valve (closed) out to the passenger side PA Ram, and make the plow angle left at the same time.

IF the B Valve did not open, the plow would go left instead.

To angle right, the fluid leaves the gear pump, and goes through the filter,
through the B Valve (closed) and to the C Valve which should be open (Coil
has magnetism), sending the fluid to the driver's side PA Ram, making the
plow go right.

IF the C Valve did not open, the plow would go left instead of right.

This is why you need to have the plow on the truck to troubleshoot. At least here in my shop, you cannot bring me a pump and ask me to troubleshoot it. I can't risk contaminating the fluid in the Test Stand, so I need the truck with the plow on it. Also, it may be a controller or wiring problem, and nothing wrong with the pump. So that is another reason why it is best to troubleshoot it on the truck.

Cut Away view of E-47/57 Sump Base casting - http://www.meyerplows.info/meyer-plo...away-view.html
Cut Away view video explaining the path of fluid flow - https://youtu.be/-Fq5am3B9sY
Testing B and C Valves video - https://youtu.be/pt9p1YiR2vE

~Admin