Hydraulic Solenoid Valve Coils - Toro Multi Pro 1750 Service Manual

Hydraulic Solenoid Valve Coils

The Multi Pro 1750 hydraulic system uses several hy-
draulic solenoid valve coils for system control. The hy-
draulics enable valve assembly includes one (1)
solenoid valve (Fig. 77). The boom lift control manifold
includes five (5) solenoid valves (Fig. 78). The brake
hold valve in the brake system also includes a solenoid
valve (Fig. 79). When the solenoid coils are energized,
hydraulic valve shift occurs to control hydraulic flow.
Testing of the coils can be done with the coil installed on
the hydraulic valve.
Testing
1. Park machine on a level surface, stop spray pump,
stop engine and engage parking brake.
2. Locate solenoid valve coil to be tested and discon-
nect wire harness connector from coil.
NOTE: Prior to taking small resistance readings with a
digital multimeter, short the meter test leads together.
The meter will display a small resistance value (usually
0.5 ohms or less). This resistance is due to the internal
resistance of the meter and test leads. Subtract this val-
ue from from the measured value of the solenoid you are
testing.
NOTE: Solenoid coil resistance should be measured
with solenoid at approximately 68F (20C). Resistance
may be slightly different than listed at different tempera-
tures. Typically, a failed solenoid coil will either be
shorted (very low or no resistance) or open (infinite re-
sistance).
3. Using a multimeter (ohms setting), measure resis-
tance between the two (2) connector terminals on the
solenoid valve coil. The resistance for all solenoid coils
used on Multi Pro 1750 machines should be 8.8 ohms.
4. If solenoid coil resistance is incorrect, replace coil
(see Hydraulics Enable Valve Assembly in Chapter 4 −
Hydraulic System, Boom Lift Control Manifold Service in
Chapter 4 − Hydraulic System, or Brake Hold Valve in
Chapter 8 − Chassis in this manual).
NOTE: Because the five (5) solenoid valve coils on the
boom lift control manifold are identical, they can be ex-
changed to assist in troubleshooting. If the problem fol-
lows the exchanged coil, an electrical problem likely
exists with the coil. If the problem remains unchanged,
something other than the solenoid coil is the problem
source (e.g. switch, circuit wiring, hydraulic problem).
5. After testing is completed, connect wire harness
electrical connector to the solenoid valve coil.
Electrical System
1
1. Gear pump
2. Hydraulics enable valve
4
3
1. Boom lift manifold
2. Coil (S1) (enable)
3. Coil (S2) (RH raise)
3
1. Brake master cylinder
2. Brake hold valve
Page 5 − 58
2
3
Figure 77
3. Solenoid valve coil
6
2
5
Figure 78
4. Coil (S2) (RH lower)
5. Coil (S3) (LH raise)
6. Coil (S3) (LH lower)
2
Figure 79
3. Brake hold coil
Multi Pro 1750
1
1