Cub Cadet 900 series, Professional Shop Manual

Page: 106 / 198

ELECTRICAL SYSTEM
100
3. Top left rounded-shape: Yellow wire
• Behavior : When the terminal is probed (yellow
wire), there should be continuity to ground when
the seat is empty.
• Circuitry : The yellow wire leads to the seat
safety switch, where it finds a path to ground
when the seat is empty.
NOTE: The yellow wire also branches off to the
PTO switch. If the PTO is “on” and the key
switch is turned to the “off” position, the yellow
wire will get a ground through the key switch.
• Interpretation : If behavior is correct, the seat
safety circuit is good. If there is continuity to
ground when the seat is occupied, the switch
may be inoperative, the PTO is on while the key
switch is off or there may be a short to ground in
the wire leading to it. If there is not continuity to
ground when the seat is empty, the switch may
be inoperative or there may be an open condi-
tion in the wire leading to it.
4. Top right middle square-shape: There is a red
wire with black trace between yellow wire and
the green wire. This wire provides the module
with input from the
reverse switch.
• Behavior : When the tractor is in reverse, this
terminal should have continuity to ground.
• Circuitry : This wire runs directly to the reverse
safety switch.
• Interpretation : Continuity to ground when the
tractor is not in reverse would indicate a short to
ground. This could take the form of a chafed wire
contacting ground or a shorted reverse safety
switch.
Lack of continuity to ground would indicate:
• A broken or disconnected wire leading to
the reverse safety switch
• A switch that is not closing because of
physical damage or corrosion.
• Loss of ground to the reverse switch.
5. Top right rounded-shape and the bottom right
square shape: are green wires.
• Behavior : The green wires should always have
continuity to ground .
• Circuitry : The green wires leads to ground.
• Interpretation : If this ground path is not good,
there will probably be other ground-related
issues with the tractor: slow starter motor, slow
battery charge, dim lights. All ground connec-
tions should be mechanically secure and corro-
sion free.
6. Bottom left square-shape: The red wire on the
OCR plug carries
battery voltage .
• Behavior : With key switch in any of the run posi-
tions, D.C. battery voltage should show-up on a
volt meter when the red probe is touched to this
terminal and the black probe is grounded.
• Circuitry : This wire draws power from the A1
terminal on the key switch.
• Interpretation : If there is not battery voltage at
this terminal, the tractor is probably not func-
tional at all. Look for a blown fuse or a bad key
switch.
7. Bottom left middle square-shape: There is a
black wire with a white trace between the red
wire and the white wire. This wire provides the
module with input from the
park brake switch.
• Behavior : When the brake pedal is depressed
and the park brake is set, a ground path is estab-
lished through the black wire with a white trace..
• Circuitry : This wire runs to the brake switch,
then on to the park brake switch..
• Interpretation : Continuity to ground when the
park brake is not set would indicate a short to
ground. This could take the form of a chafed wire
contacting ground or a shorted reverse safety
switch.
Lack of continuity to ground would indicate:
• A broken or disconnected wire leading to
the brake or park brake switches
• A switch that is not closing because of
physical damage or corrosion.
• Loss of ground to the park brake switch.
8. Bottom right middle rounded-shape: The white
wire provides a
ground signal to the RMC mod-
ule when the key switch is placed in the
REVERSE CAUTION MODE.
• Behavior : There should be continuity to ground
at this terminal when the key switch is in the
REVERSE CAUTION MODE position.