How our starters work

[VetteVet]

This may help a lot of you understand how the starter works and be able to trouble shoot them.


The starter cycle starts with the key switch turned to the ST position and power is routed via a 12 gauge purple wire to the neutral safety switch on automatics, and to a neutral or safety switch on the transmission, and some times on the later models, to a clutch switch. From there it goes through the firewall block to the S terminal on the starter solenoid.





The solenoid is an electromagnetic device that also acts a relay. The electromagnetic function pulls the starter bendix lever and throws out the starter gear to engage the flywheel.

At the same time the contact washer in the solenoid inside near the rear, moves to the rear and joins the two main terminals on the starter. The battery cable at the top and the starter field terminal at the bottom.
Note the red arrows.



This feeds battery power to the starter windings through the starter brushes and spins the starter armature turning the starter gear and the flywheel.

When the key is released the key switch goes to the ignition position and
releases power to the solenoid and a spring inside the solenoid returns it to the forward position breaking the contact on the two main terminals for the starter and the cycle stops.
shown below.

[Andy4639]

VetteVet you are just amazing man! Great write up. This needs to be put in the electrical stickeys!

[franken]

Nice but the large + cable doesn't go through the junction block as suggested in pic #1.

[70cst]

Great info