Starter Motor Silence

[Alan C]

I get no response from my starter motor when the ignition is activated nor any sign of a power drop. Is the motor likely to have failed or could it be a earth issue in which case where is the earth that connects the motor, I'm guessing it would be pretty substantial.

[PaulGover]

The normal way to earth a starter motor is through the fact that it's mounted on the engine, and that's all earth!

If there's no sign of a voltage drop when you try to start, the common culprit is the starter relay or the solenoid. The ignition switch is nowhere big enough to handle the current involved - typically 500-1000 A. There should be diagnostic codes if you have an ODB reader.

To quote the workshop manual

The starting system consists of a pre-engaged type starter motor, battery, remote control switch (ignition switch) and relay. When the starter is operated from the ignition switch, the engagement lever moves the pinion into mesh with the engine ring gear teeth, the electrical contacts within the solenoid complete the high power circuit and the starter motor operates to turn the engine.

Vehicles equipped with automatic transmission have a transmission range sensor attached to
the circuit which prevents operation of the starter motor unless NEUTRAL or PARK are
selected.
The sequence of operation is as follows:
Ignition switch in the start position III.
Starter relay activated.
Voltage provided to the starter motor solenoid.
Starter solenoid engages the drive pinion to the flywheel or flexiplate.
Starter solenoid switches the battery current to the starter motor.
System remains engaged until the ignition switch is returned to the run position