Glow And Main Power Relays - Toro Groundsmaster 4700-D Service Manual

Glow and Main Power Relays

The glow and main power relays are located at the pow-
er center behind the operator seat (Fig. 34). These re-
lays are attached to the wire harness with a four (4) wire
connector (Fig. 35).
The glow relay is used to provide current to the engine
glow plugs when energized by the TEC--5002 controller.
The TEC--5002 controls and monitors the operation of
the glow relay.
The main power relay is used to provide current to the
TEC controllers and most of the fuse protected circuits
(headlights, operator seat, power point and optional
electric equipment). When the ignition switch is in the
ON or START position, the main power relay is ener-
gized.
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. Remove cover from power center and locate relay to
be tested.
4. Disconnect wire harness connector from relay. Re-
move relay from mounting bracket for testing.
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 component you
are testing.
5. Using a multimeter, verify that coil resistance be-
tween terminals 86 and 85 is approximately 72 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.
Electrical System
7. Disconnect voltage and test leads from the relay ter-
minals.
8. Secure relay to mounting bracket and connect wire
harness connector to relay. Install cover to power center.
9. Connect positive (+) cable to battery and then con-
nect negative (--) cable to battery (see Battery Service
in the Service and Repairs section of this chapter).
1
4
5
6
1. Lock nut
2. Main power relay
3. Glow relay
86
85
Page 5 - - 26
3
1
2
Figure 34
4. Start relay
5. Flange head screw
6. Mounting bracket
87
30
85
87
30
Figure 35
Groundsmaster 4500--D/4700--D
5
86