Electrical
Ignition Switch
The ignition switch controls the start and power circuits from the key or button.
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Starting & charging flow
Interactive — tap a partTap a part to see how it fits in the system.
What it does
- Feeds power to ignition and accessories
- Energizes the starter circuit
- Modern cars use start-stop buttons with the switch as a module
When it fails
- Car will not crank
- Accessories dead or intermittent
- Engine dies while driving
- Key feels loose or binds
How to diagnose
- Test for power at the switch terminals
- Check the start signal with a test light
- Wiggle the key to reproduce the fault
Maintenance
- Replace the switch if intermittent
- Never hang heavy key rings on the switch
Use the diagnosis order. When a part fails, confirm each hypothesis with measurements before replacing anything — codes and symptoms overlap.
Related part
Starter Motor
The starter cranks the engine with a high-torque electric motor and pinion gear.