1. Battery and Electrical System:
* Battery Voltage: This is the MOST common cause. Use a voltmeter to check the battery voltage. It should read around 12.6 volts when the car is off. If it's significantly lower, the battery is dead or weak. Try jump-starting it. If it cranks with a jump, you need a new battery.
* Battery Cables: Inspect the battery cables (positive and negative) for corrosion, looseness, or damage. Clean the terminals thoroughly with a wire brush and baking soda solution. Make sure the connections are tight.
* Alternator: Even with a good battery, a faulty alternator might not be charging the battery properly. Check the alternator's output voltage while the engine is running (should be around 13.5-14.5 volts). A low voltage reading indicates a failing alternator.
* Fuses and Relays: Check the fuses and relays related to the ignition system and starter. A blown fuse or a bad relay will prevent the starter from receiving power. Consult your owner's manual for fuse box locations and diagrams. Pay close attention to any fuses marked "starter," "ignition," or "power."
* Ignition Switch: A faulty ignition switch can prevent power from reaching the starter. This is less common but possible.
2. Security System (if equipped):
* Immobilizer: Some 1998 models might have an immobilizer system. If the key isn't recognized, the system might be preventing the starter from engaging. Try a different key if you have one. If you have a spare key and that doesn't work, you may have an immobilizer issue.
3. Neutral Safety Switch (Automatic Transmission):
* Transmission in Park/Neutral: Make absolutely sure the transmission is in Park (or Neutral if it's a manual). The neutral safety switch prevents starting unless the transmission is in the correct gear. A faulty switch can prevent starting even if the gear selector is in the right position.
4. Starter Wire Connections:
* Wiring Harness: Even with a new starter, the wiring harness leading to the starter could be damaged or have poor connections. Inspect the wires carefully for breaks, chafing, or loose connections. This includes the large power cable and smaller control wires.
5. Other Less Likely Possibilities:
* Solenoid: While you replaced the starter, the solenoid (part of the starter that engages the gear) might be faulty even on a new starter. (though less likely).
* Grounds: Poor ground connections in the electrical system can prevent current from flowing properly to the starter. Check all ground straps and ensure they're clean and tight.
Troubleshooting Steps:
1. Start with the simplest checks: battery voltage and cable connections.
2. Check fuses and relays.
3. Verify the transmission is in Park/Neutral.
4. If none of the above work, carefully inspect the wiring harness going to the starter.
5. If you're uncomfortable working with car electrical systems, take it to a mechanic for diagnosis. They have the tools and expertise to pinpoint the problem quickly and efficiently.
Ignoring a low battery voltage will eventually damage the battery further and lead to potentially costly repairs or even more critical problems. Always prioritize checking the battery first.
