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Groundsmaster 5900/5910Page 5 -- 48Electrical System
Intake Air Heater Contactor
The intake air heater contactor is used on the Ground-
smaster 5900 and 5910to providecurrent for the engine
intake air heater. The contactor is attached to a frame
bracket behind the batteries (Fig. 87). The contactor is
energized by the engine ECM when low temperatures
are detected prior to starting the engine.
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) that is due to the internal resistance of
the meter and test leads. Subtract this value from the
measured value of the component you are testing.
1. Park machine on a level surface, lower cutting
decks, stop engine, engage parking brake and remove
key from the ignition switch. Raise and support hood to
access intake air heater solenoid.
2. Disconnect battery cables from battery terminals
(see Battery Service in the Service and Repairs section
of this chapter).
3. Locate contactor. Note wire connector locations on
contactor for assembly purposes. Disconnect all har-
ness electrical connectors from contactor.
4. Usingjumper wires,apply12VDCdirectlyacrossthe
contactorcoilposts(Fig.88).The contactor should click.
With the contactor coil energized, resistance across the
contactor main posts should be less than 1 ohm.
5. Remove voltage from contactor coil posts. The con-
tactorshouldclick.Withthecontactor coil not energized,
resistance across the contactor main posts should be
infinite ohms.
6. With voltage removed from all contactor posts, mea-
sure resistance acrossthe contactor coil posts (Fig. 88).
Resistance of the coil should be approximately 13.5
ohms.
7. With voltage removed from all contactor posts, mea-
sure resistance across the contactor main posts (Fig.
88). Resistance should be infinite ohms.
8. If testing determines that contactor is faulty, replace
contactor.
9. After testing, connect harness connectors to contac-
tor.
10.Connect battery cables to battery terminals(seeBat-
tery Service in the Service and Repairs section of this
chapter).
1. Air heater contactor 2. Mega fuse holder
Figure 87
2
1
2
Figure 88
1. Contactor
2. Main post
3. Coil posts
2
3
1
3
2