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--Dand4700--Dmachines.Whenenergizedbythe
TECcontroller,thesecoilsprovidehydrauliccircuitcon-
trol.
Two (2) different solenoid valve coils are used on the
4500--Dand4700--D.Acoilcanbeidentifiedbymeasur-
ingit’sheight and diameter (Fig.38).Testingofthecoils
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 coil 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 r eadings 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
resistanceofthe meterandtestleads.Subtractthis val-
uefromfromthemeasuredvalue of the componentyou
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
withsolenoidatapproximately68
o
F(20
o
C).Resistance
maybeslightlydifferentthan listed atdifferenttempera-
tures. Typically, a failed solenoid coil will either be
shorted (very low or no r esistance) or open (infinite re-
sistance).
5. If solenoid coil resistance is incorrect, replace sole-
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
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