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Groundsmaster 4500--D/4700--DPage 5 -- 28Electrical System
Hydraulic Solenoid Valve Coils
Numerous hydraulic solenoid valve coils are used on
the hydraulic control manifolds of Groundsmaster
4500--D and 4700--D machines. Whenenergized by the
TEC controller,these coils provide hydrauliccircuit con-
trol.
Two (2) different solenoid valve coils are used on the
4500--D and4700--D.Acoilcanbeidentifiedbymeasur-
ing it’s height and diameter (Fig.38). Testing of the coils
can be done with the coil remaining on the hydraulic
valve.
NOTE: To assist in troubleshooting, identical solenoid
coils can be exchanged. If the problem follows the ex-
changed coil, a problem with the coil likely exists. If the
problem remains unchanged, something other than the
solenoid coil is the problem source (e.g. switch, circuit
wiring, hydraulic problem).
Testing
1. Park machine on a level surface, lower cutting
decks, stop engine, engage parking brake and remove
key from the ignition switch.
2. Locate hydraulic valve solenoid c oil to be tested.
Identify coil by measuring the coil diameter and coil
height (Fig. 38).
3. Disconnect 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 andtest leads. Subtract thisval-
ue from from the measured value of the component you
are testing.
4. Using a multimeter (ohms setting), measure resis-
tance between the two (2) connector terminals on the
solenoid valve coil. The correct resistance for the sole-
noid coil is identified below:
COIL
DIAMETER
COIL
HEIGHT
COIL
RESISTANCE
1.84 in
(46.7 mm)
1.96 in
(49.9 mm)
7.1 ohm
1.41 in
(35.8 mm)
1.43 in
(35.8 mm)
8.8 ohm
NOTE: Solenoid coil resistance should be measured
with solenoidat approximately68
o
F(20
o
C).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).
5. If solenoid coil resistance is incorrect, replace s ole-
noid (see Hydraulic Solenoid Valve Coil Removal and
Installation in the Service and Repairs section of this
chapter).
6. After testing is completed, connect wire harness
connector to the solenoid.
Figure 38
COIL
DIAMETER
COIL
HEIGHT