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Groundsmaster 4500--D/4700--DPage 5 -- 38Electrical System
Relays with Five (5) Terminals
Your Groundsmaster uses a number of electrical relays
that have five (5) terminals. A tag near the wire harness
relay connector can be used to identify each relay.
The main relay is used on models 30873 and 30874 to
provide current for several engine components when
energized by the engine electronic control unit (ECU).
The rack actuator relay is used on models 30873 and
30874 to provide current for the engine rack a ctuator
when energized by the engine ECU.
The EGR relay is used on models 30881 and 30882 to
provide current to the engine EGR valve when ener-
gized by the engine ECU.
The main, rack actuator and EGR relays are a ttached to
the air cleaner mount bracket near the engine ECU (Fig.
42).
Testing
1. Park machine on a level surface, lower cutting
decks, stop engine, engage parking brake and remove
key from the ignition switch.
2. To make sure that machine operation does not occur
unexpectedly, disconnect negative (--) cable from bat-
tery and then disconnect positive (+) cable from battery
(see Battery Service in the Service and Repairs section
of this chapter).
3. Locate relay that is to be tested.
4. Disconnect wire harness connector from relay. Re-
move relay from mounting bracket for testing.
5. Using a multimeter, verify that coil resistance be-
tween terminals 85 and 86 is from 71 to 88 ohms.
6. Connect multimeter (ohms setting) leads to relay ter-
minals 30 and 87. Ground terminal 86 and apply +12
VDC to terminal 85. The relay should make and break
continuity between terminals 30 and 87 as +12 VDC is
applied and removed from terminal 85.
7. Disconnect voltage from terminal 85 and multimeter
lead from terminal 87.
8. Connect multimeter (ohms setting) leads to relay ter-
minals 30 and 87A. Apply +12 VDC to terminal 85. The
relay should make and break continuity between termi-
nals 30 and 87A as +12 VDC is applied and removed
from terminal 85.
9. After testing, disconnect voltage and multimeter test
leads from the relay terminals. Secure relay to mounting
bracket and connect wire harness connector to relay.
10.Secure all removed components to machine.
11.Connect positive (+) cable first t o battery and then
connect negative (--) cable t o battery (see Battery Ser-
vice in the Service and Repairs section of this chapter).
1. Air cleaner mount
2. Engine ECU mount
3. 5 terminal relay
4. Cap screw
5. Flange nut
Figure 44
5
1
3
2
4
FRONT
Figure 45
86
85
87A 87
30
2
1
3
4
1. Coil terminal
2. Common terminal
3. Normally closed term.
4. Normally open term.
1