1. Low or Dead Battery: This is the most probable cause. The interior lights staying on while attempting to start indicate the battery is discharging rapidly, and it might not have enough power to even crank the engine. The radio turning off is another indicator of low voltage.
* Check the Battery Terminals: Inspect the battery terminals for corrosion. Clean them with a wire brush and baking soda solution if necessary. Ensure they are tightly connected.
* Test the Battery Voltage: Use a multimeter to measure the battery voltage. A fully charged battery should read around 12.6 volts. Anything significantly lower indicates a weak or dead battery. A voltage reading close to 12 when trying to start means your battery may be unable to supply enough current to handle the starting load.
* Jump Start: Try jump-starting the vehicle from a known good battery. If it starts, the problem is likely the battery itself.
2. Faulty Alternator: If the battery was recently charged or replaced, and this problem still occurs, the alternator might not be charging the battery. This would cause the battery to drain over time, eventually leading to the symptoms you're experiencing.
* Check the Battery Voltage While the Engine is Running: After jump starting the car, let it run for 10-15 minutes. Check the battery voltage again with the multimeter. It should read around 13.5-14.5 volts if the alternator is working correctly. A voltage reading of around 12 indicates the alternator is likely faulty.
3. Faulty Starter Motor: Less likely given the other symptoms, but a faulty starter motor can also prevent the engine from cranking. However, a bad starter would likely not affect the interior lights or radio in the same way as a battery/alternator issue.
* Listen for Clicking: When you turn the key, do you hear a clicking sound from the starter area (usually near the engine)? This can indicate a faulty starter solenoid or other starter motor problems.
4. Wiring Issues: While less common, there could be a short circuit somewhere in the vehicle's electrical system that's causing excessive drain on the battery. This is harder to diagnose and may require a professional electrician.
5. Parasitic Drain: Even with the key off, something in your car might be drawing power from the battery. This is possible if an accessory is left on or there's a short somewhere. A multimeter can help you find if current is being drawn when the car should be off.
Troubleshooting Steps:
1. Start with the simplest: Check the battery terminals and test the battery voltage (both with the engine off and on, if you can get it running).
2. Jump start: This will help determine if it's a battery problem.
3. If the jump start works, check the alternator voltage.
4. If neither resolves the issue, consider the starter and parasitic drain.
If you're not comfortable working on car electrical systems yourself, it's best to take your Venture to a mechanic or auto parts store for diagnosis. Ignoring this could lead to further damage to your battery or other components.
