if it's a big wire about 1/2' thick, it is the battery cable from the battery positive post to the starter, it provides the heavy current to run the starter.
Another small wire is the 12 volts low current that activates the starter relay which in turn connects the battery cable to the starter motor.
what is starter doing or not doing?
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Starter System
The starting system cranks the engine at a speed fast enough to permit the engine to start.
- Heavy cables, connectors and switches are used in the starting system because of the large current required by the starter motor (11002) while it is cranking the engine.
- The amount of resistance in the starting circuit must be kept to an absolute minimum to provide maximum current for starter motor operation.
- A discharged or damaged battery (10653) , loose or corroded connections or partially broken cables will result in slower-than-normal cranking speeds. These concerns may even prevent the starter motor from cranking the engine.
- In case of starting system difficulty, the operator may have discharged the battery before calling for assistance.
- A road service procedure is described in this section to aid the service technician in such cases of a discharged battery .
The starting system includes the following:
- the permanent magnet gear-reduction starter motor with a solenoid-actuated drive
- the battery
- a remote control starter switch (part of the ignition switch (11572) )
- the transmission range (TR) sensor
- the starter solenoid (11390)
- heavy circuit wiring
Vehicles equipped with an automatic transmission have a transmission range (TR) sensor in the starter control circuit. This sensor prevents operation of the starter motor unless the transmission range selector lever is in the NEUTRAL or PARK position.
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