Cub Cadet 900 Series Professional Shop Manual page 101

• Symptom-No crank and no starter solenoid
click: Power is not getting to the trigger spade on
the starter solenoid. Test for proper battery volt-
age. Then check for power where the fused red
wire with white trace connects to the B terminal.
Check for continuity between B and S terminals
in START position. If power is getting to the S
terminal in the START position, the problem lies
down-stream in the starter circuit; Check conti-
nuity from the orange wire on the S terminal to
the orange wire with white trace on the trigger
spade on the starter solenoid. If it is broken,
trace through the brake and PTO switches.
• Symptom-No crank, solenoid click: The problem
lies in the heavy-gauge side of the starter circuit;
battery cables, starter cable, solenoid, or ground
issue.
• Symptom-Crank, spark, but not fuel: First test
for power at the solenoid, if no power then check
for continuity from B to A1 in the START posi-
tion. If power is reaching the red wire that con-
nects to the A1 terminal in the start position, the
problem lies down-stream of the key switch. A
handy quick-check is to apply power to the red
wires where they connect to the S terminal
(whole circuit) or directly to the after fire solenoid
to listen for the audible "click" that it makes when
functioning.
• Symptom-Crank, but no spark: This is a highly
unlikely scenario. If it occurs after a key switch
has been changed independently of the RMC
module, this would arouse suspicion that the
wrong key switch was installed. Otherwise, the
problem lies elsewhere in the safety circuits or
engine. Do not over-look the possibility of a bad
magneto or chafed ground lead within the
engine harness.
3. In the NORMAL RUN position (green zone), the
B and A1 terminals should have continuity. Once
the engine is running, the alternator produces
current that tracks-back to charge the battery,
via the red wire connected to the B terminal.
• Symptom-Battery does not charge: Follow the
engine manufacturer's recommendations for
testing alternator output. If alternator output is
getting to and through the key switch, but not
reaching the battery, the fuse may have blown
after start-up. A blown fuse will disable the
starter circuit. A simple quick-test for the pres-
ence of alternator output at the battery is to
check across the battery posts for DC voltage.
• Symptom-After fire solenoid does not work:
engine starts and dies: The after fire solenoid is
powered directly by the red wire from the B ter-
minal of the key switch, and should operate
independently of anything else on the tractor
once the engine is running. If the alternator fails
and battery power is not reaching the after fire
solenoid through the key switch, it will not work.
This is an unusual set of circumstances.
4. In the REVERSE CAUTION MODE (yellow
zone), the same characteristics are true as for
the normal run position, but in addition the L ter-
minal will have continuity with the A2 terminal.
The A2 terminal is connected to the RMC mod-
ule by a purple wire (electric PTO) or a white
wire (manual PTO). The L terminal (formerly
used for the lighting circuit) connects directly to
the ground circuit of green wires. When the key
is in the REVERSE CAUTION MODE position,
the purple wire carries a ground signal to the
RMC module. When the parking brake is not set,
this ground signal arms (enables), but does not
turn-on the RMC module.
• Symptom-RMC module will not turn-on: Check
for continuity between A2 and L terminals on the
key switch when it is in the REVERSE CAUTION
MODE position. Confirm that the green wire has
continuity to ground. If the switch is capable of
establishing a ground signal to the RMC module,
the problem is likely to lie elsewhere in the sys-
tem.
• Symptom-RMC module will not turn-on: confirm
that the ground path (continuity to ground) to the
purple or white wire is broken when the key
switch is in any position other than REVERSE
CAUTION MODE. The RMC module is disarmed
(disabled) when the parking brake is set. To re-
arm the module, the key is moved to another
position, breaking the ground signal, then
returned to the REVERSE CAUTION MODE, re-
establishing the ground signal. It works some-
thing like a latched relay. If it is not possible to
break the ground-path, it is not possible to
freshly establish it either, and the RMC module
will not be armable. Causes for such a condition
might include a shorted or incorrect key switch,
or a chafed purple wire shorting to ground
between the key switch and the RMC module.
ELECTRICAL SYSTEM
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