Service Manual

Groundsmaster 4500−D/4700−D Page 5 − 27 Electrical System
Component Testing
For accurate resistance and/or continuity checks, elec-
trically disconnect the component being tested from the
circuit (e.g. unplug the ignition switch connector before
checking continuity of the switch terminals).
NOTE: For engine component testing information, see
the Yanmar Service Manual and Yanmar Troubleshoot-
ing Manual.
CAUTION
When testing electrical components for continu-
ity with a multimeter (ohms setting), make sure
that power to the circuit has been disconnected.
Ignition Switch
The ignition (key) switch on the console arm has three
(3) positions (OFF, ON/PREHEAT and START).
Testing
NOTE: Before disconnecting the ignition switch for
testing, the switch and its circuit wiring should be tested
as a TEC electrical input using the InfoCenter Display
(see InfoCenter Display in this chapter). If input testing
verifies that the ignition switch and circuit wiring are
functioning correctly, no further ignition switch testing is
necessary. If, however, input testing determines that the
ignition switch and circuit wiring are not functioning cor-
rectly, proceed with the following ignition switch testing
procedure.
1. Park machine on a level surface, lower cutting
decks, engage parking brake and stop engine. Remove
key from ignition switch.
2. Remove console arm covers to gain access to igni-
tion switch (see Console Arm in the Service and Repairs
section of Chapter 7 − Chassis).
3. Disconnect wire harness connector from ignition
switch.
4. The ignition switch terminals are identified in Figure
25 and the circuitry of the switch is shown in the chart in
Figure 26. With the use of a multimeter (ohms setting),
the switch functions can be tested to determine whether
continuity exists between the various terminals for each
switch position. Verify continuity between switch termi-
nals.
5. Replace ignition switch if testing determines that it is
faulty.
6. If the ignition switch tests correctly and a circuit prob-
lem still exists, check wire harness (see Electrical Sche-
matics and Wire Harness Drawings in Chapter 9 −
Foldout Drawings).
7. After testing is complete, connect machine wire har-
ness connector to ignition switch. Secure console arm
covers to machine with removed fasteners (see Con-
sole Arm in the Service and Repairs section of Chapter
7 − Chassis).
Figure 25
REAR VIEW
FRONT VIEW
START
OFF
ON/PREHEAT
3
2
4
5
6
1
SWITCH
POSITION
CIRCUITS
OFF 1 + 6, 4 + 5
ON/PREHEAT 1 + 3 + 4 + 5 + 6
START 1 + 2 + 4 + 5 + 6
Figure 26
NOTE: Ignition switch terminals 1 and 6 are connected
internally. Terminals 4 and 5 are also connected internal-
ly. These terminals should have continuity regardless of
switch position.
Electrical
System