1. The New Alternator is Faulty:
* It's possible, though unlikely, that the new alternator is defective right out of the box. Test the alternator output with a voltmeter to confirm it's generating the correct voltage.
* Incorrect Installation: Make sure the alternator is properly mounted and its wiring connections are secure and tight. Double-check the polarity (positive and negative) of the wiring.
2. Issues with the Battery:
* Battery Age/Condition: Even if the battery is new, it might be faulty or simply too old to hold a charge properly. Test the battery's voltage and specific gravity (if you have a hydrometer) to assess its condition.
* Battery Terminal Corrosion: Look for corrosion on the battery terminals. Clean them thoroughly with a wire brush and battery terminal cleaner.
3. Wiring Problems:
* Loose or Corroded Connections: Inspect all wiring connections related to the charging system, including those on the battery, alternator, starter, fuse box, and the vehicle's electrical system. Clean and tighten any loose or corroded connections.
* Damaged Wiring: Check for any frayed, broken, or melted wires. Replace any damaged wiring.
4. Regulator Issues:
* Internal Regulator Failure: Some alternators have an internal voltage regulator. If this fails, the alternator won't produce the correct charging voltage. A replacement alternator may have a bad regulator if it came from a salvage yard.
5. Other Electrical Components:
* Charging System Control Module (if equipped): This module may be faulty, preventing the alternator from functioning properly.
* Sensors: The charging system uses sensors like the battery voltage sensor to monitor charging. A faulty sensor could be giving incorrect signals.
Troubleshooting Steps:
1. Voltage Check: With the engine running, use a voltmeter to check the battery voltage. It should be around 13.5 to 14.5 volts. If it's significantly lower, the alternator is likely not charging.
2. Alternator Output Test: You can usually test the alternator's output directly at the alternator terminals with a voltmeter. Consult your car's repair manual for specific test procedures.
3. Inspect Wiring: Carefully inspect all the wiring and connections related to the charging system for damage or corrosion.
4. Battery Test: Have the battery tested at an auto parts store to ensure it's in good working condition.
Important Notes:
* Safety First: Work on the charging system can involve live electrical components. Always disconnect the battery negative terminal before working on the system to avoid electric shock.
* Consult a Manual: Refer to your 1988 Honda Accord's repair manual for detailed troubleshooting and testing procedures.
* Professional Help: If you're not comfortable with electrical troubleshooting, it's best to consult a qualified mechanic.
