Based on the information you provided, it appears that the previous owner of the 1999 Camaro installed a jumper wire from the MAP (manifold absolute pressure) sensor to provide current to the alternator. This modification bypasses the normal charging circuit and may be the cause of the alternator not charging. Here's a potential cause and solution to address the issue:
Cause: Faulty MAP Sensor Wiring
The MAP sensor provides a voltage signal to the engine control module (ECM) based on the pressure in the intake manifold. When the jumper wire is connected from the MAP sensor to the alternator, it may interfere with the proper functioning of the MAP sensor circuit, resulting in incorrect voltage readings and causing the ECM to mismanage the charging system.
Solution:
To resolve this issue, you should remove the jumper wire and restore the original wiring configuration. Here are the steps to follow:
1. Disconnect the Battery:
- Disconnect the negative (-) battery terminal to ensure safety while working on the electrical system.
2. Locate the Jumper Wire:
- Find the jumper wire that was installed by the previous owner, connecting the MAP sensor to the alternator.
3. Remove the Jumper Wire:
- Carefully disconnect the jumper wire from both the MAP sensor and the alternator.
4. Inspect Wiring Connectors:
- Inspect the wiring connectors on the MAP sensor and the alternator to ensure they are clean and free of any damage.
5. Restore Original Wiring:
- Reconnect the original wiring harness to the MAP sensor and the alternator.
6. Reconnect the Battery:
- Reconnect the negative (-) battery terminal to restore power to the electrical system.
7. Test Charging System:
- Start the vehicle and use a multimeter to measure the voltage across the battery terminals. It should read around 14 volts with the engine running, indicating that the alternator is charging properly.
By eliminating the jumper wire and restoring the proper wiring configuration, you can address the potential issue caused by the modification and ensure that the alternator is receiving the correct signals from the MAP sensor and the ECM. This should resolve the problem with the alternator not charging.
Note:
If the alternator still fails to charge after removing the jumper wire, there may be other underlying issues with the alternator, wiring, or electrical system that require further diagnosis and repair. In this case, it is recommended to seek assistance from a qualified mechanic or auto electrician to accurately diagnose and fix the problem.
