White Outdoor LT-5 Service Manual page 35

Electrical Diagnostic Over-view
17.1-17.9 Key Switch and Module
17.3 Key Switch OFF
17.4 Key Switch START
17.5 Key Switch RUN
17.6 Key Switch REVERES CAUTION
17.9 Module Function
17.1O-17.24 Single-point Diagnosis
17.11-17.23 RMC Plug Test
17.14-17.17 Pigtail Plug Test
17.16 Pigtail Plug Test: seat safety
17.17 Pigtail Plug Test: PTO safety
17.19 RMC Plug Test: reverse safety
17.2O RMC Plug Test: ground
17.21 RMC Plug Test: power
17.22 RMC Plug Test: park-brake
17.23 RMC Plug Test: module arm signal
17.25-17.31 Direct testing of switches
17.25 Direct test: PTO safety switch
17.26 Direct test: Brake safety switch
17.27 Direct test: park brake safety switch
17.28 Direct test: reverse safety switch
17.29 Direct test: seat safety switch
17.3O Direct test: starter solenoid
17.31 Lighting circuit
17.32 Fuse and Ammeter
17.33 Engine harness connector: White
17.34 Engine harness connector: Troy-Bilt
17.35 Voltage drop test
17.2. The Key Switch is similar to those used in a
variety of MTD applications since 1999. The dif-
ference in this case is that it is incorporated in
the same housing as the RMC module; the two
items are not available separately.
See Figure 17.2.
Figure 17.2
Ammeter
RMC Module
Key switch
31
700 SERIES LAWN TRACTORS
17.3. In the OFF position, continuity can be found
between the M, G, and A1 terminals.
See Figure 17.3.
Figure 17.3
• M is connected to the magneto by a yellow wire,
G is connected to ground by a green wire, and
A1 is connected to the after fire solenoid and
alternator.
• In the OFF position, the magneto primary wind-
ings are grounded, disabling the ignition system.
The alternator output that normally keeps the
after fire solenoid powered-up is given a more
direct path to ground, depriving the after fire
solenoid of power. This turns-off the fuel supply.
• Symptom-engine runs with key in OFF position:
The key switch is not completing the path to
ground either because of an internal fault or a
bad ground connection elsewhere in the har-
ness. Check continuity between M, G, and A1
terminals with key switch in OFF position.
Check green wire continuity to ground.
• Symptom-loud "BANG" when key is turned to
the OFF position: The after fire solenoid is not
closing, either because it is physically damaged
or the alternator output is not getting grounded.
Check continuity between G and A1 terminals.
Check continuity from red wire to afterlife sole-
noid.
• Symptom-Engine runs 3-5 seconds after key is
turned to OFF position: The after-fire solenoid is
turning-off the fuel supply, but the ignition is con-
tinuing to operate. Check continuity between the
M and G terminals in the OFF position. Check
continuity from yellow wire connection all the
way to the spade terminal on the magneto.