* Faulty Battery: Even with new components, the battery itself could be the culprit. It might not hold a charge, even if it seems to work briefly with a jump. Get the battery load tested at an auto parts store; this is a crucial step often overlooked. A load test reveals if the battery can deliver sufficient amps under load.
* Wiring Issues (Beyond Connections): While you've cleaned connections, there might be:
* Broken or corroded wires: Inspect the wiring harness, particularly the main power cables leading to and from the battery, alternator, and starter. Look for fraying, breaks, or corrosion hidden under insulation. A visual inspection might not suffice; a multimeter can test for continuity.
* Poor ground connection: A bad ground connection between the engine block and the chassis (or battery) will prevent proper current flow. Clean and tighten all ground connections thoroughly.
* Alternator Wiring: Even though the alternator *tested* good, the problem could be with the wiring *to* the alternator. A bad connection or a corroded wire in the circuit prevents the alternator from charging the battery correctly.
* Internal Regulator Problem (in Alternator): It's possible the internal voltage regulator in the alternator isn't functioning correctly, even if the alternator itself spins freely and appears to be generating power. A more in-depth alternator test might be needed. Many auto parts stores offer this service.
* Parasitic Drain: This is a significant possibility. A parasitic drain is an electrical component that continues drawing power from the battery even when the vehicle is off. This could be anything from a faulty interior light, a malfunctioning radio, a problem with the alarm system, or something more obscure. A multimeter can measure the parasitic drain; if it's too high, you'll need to systematically disconnect components until you find the culprit.
Troubleshooting Steps:
1. Battery Load Test: This is the *most important* first step. A faulty battery will mask other problems.
2. Thorough Wiring Inspection: Visually inspect *all* wiring related to the charging system (battery, alternator, starter).
3. Check Ground Connections: Clean and tighten every ground connection you can find.
4. Parasitic Drain Test: Use a multimeter to measure the drain on the battery with the car off. The drain should be minimal (less than 50mA is generally acceptable).
5. Retest Alternator (if necessary): If the other steps don't resolve the issue, have a professional perform a more comprehensive alternator test.
If you're not comfortable working with car electrical systems, take your Astro to a qualified mechanic. Improper electrical repairs can be dangerous.
