* Battery: Even if the radio works, a weak battery might not have enough *cranking amps* to turn the engine over. Test the battery voltage with a multimeter. It should read around 12.6V when not cranking. A load test (putting a load on the battery while measuring voltage) is a better indicator of its cranking ability.
* Battery Cables/Connections: Corrosion on the battery terminals or loose connections at the battery or the starter can prevent sufficient current flow. Clean and tighten all battery cable connections.
* Starter Motor: This is the most likely culprit. The starter motor is responsible for cranking the engine. It could be failing due to worn brushes, a bad solenoid, or a seized motor. You may hear a click (solenoid engaging but motor not turning) or nothing at all when you turn the key.
* Neutral Safety Switch (NSS): This switch prevents the car from starting unless it's in Park or Neutral. A faulty NSS won't allow the starter circuit to complete.
* Ignition Switch: This switch controls the power flow to the starter. A worn or faulty ignition switch can prevent the starter from receiving power.
* Fuses/Relays: While less likely given the other electrics work, a blown fuse or bad relay specifically related to the starter circuit is possible. Check the fuse box for any blown fuses related to the starting system (consult your owner's manual).
* Wiring: A broken or corroded wire in the starter circuit can interrupt the power flow. This requires more in-depth troubleshooting.
Troubleshooting Steps:
1. Check Battery Voltage and Cables: This is the easiest and quickest check.
2. Listen Carefully When Turning the Key: Do you hear any clicking sounds? A single click is often the solenoid. No sound at all points more towards a battery or cable issue or the ignition switch.
3. Check the Neutral Safety Switch: Make sure the car is in Park or Neutral. If it's an automatic, try shifting it a few times.
4. Try Jump Starting: If you have a known good battery and jumper cables, try jump-starting the car. If it starts, it confirms a battery or charging system problem.
5. Inspect Starter Motor (Advanced): This usually requires some mechanical knowledge and may involve removing the starter to inspect it.
If you're not comfortable working on your car's electrical system, it's best to take it to a qualified mechanic for diagnosis and repair. Attempting to troubleshoot electrical issues without the proper knowledge can lead to further damage or injury.
