Toro Groundsmaster 4000-D Service Manual page 84

Engine Cooling Fan Circuit Problems
Problem
Cooling fan runs only in forward di-
rection (fan does not run in reverse
direction).
Cooling fan does not rotate.
Cooling fan always rotates at slow
speed.
Cooling fan always rotates at fast
speed.
Hydraulic System
Possible Cause
Solenoid cartridge valve (S10) in combination control manifold is
faulty.
Electrical problem exists that prevents combination control manifold
solenoid valve (S10) operation (see Chapter 5 -- Electrical System).
Cooling fan motor is worn or damaged.
Proportional relief valve (PRV) in combination manifold is stuck or
damaged.
Gear pump section for engine cooling fan circuit is worn or damaged
(NOTE: A worn or damaged gear pump section will also affect the
steering, lift/lower and traction charge circuits).
Combination manifold cartridge valve seals are leaking.
Check valve in combination manifold is not seating.
Proportional relief valve (PRV) in combination manifold is stuck or
damaged.
Hydraulic fan motor is worn or damaged.
Proportional relief valve (PRV) in combination manifold is faulty.
Electrical problem exists that prevents correct operation of combin-
ation manifold proportional relief valve (PRV) (see Chapter 5 --
Electrical System).
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