* Faulty Ignition Switch: This is a prime suspect. The ignition switch itself might be failing, either mechanically (worn parts) or electrically (internal short or broken connection). This is a relatively common problem in older vehicles.
* Steering Column Issues: Problems within the steering column, such as a worn or damaged ignition lock cylinder, can interrupt the electrical connection to the ignition system. The ignition might turn off if the steering wheel is moved in a certain way.
* Wiring Problems: Damaged, corroded, or loose wires in the ignition circuit can cause intermittent power loss. This includes wires connecting the ignition switch to the battery, the engine control module (ECM), and other components.
* Low Battery Voltage: A weak battery can cause inconsistent power delivery, leading to the ignition shutting off, especially under load (like when running accessories).
* Faulty Neutral Safety Switch: This switch prevents the car from starting unless it's in park or neutral. A faulty switch can interrupt the ignition circuit.
* Problems with the ECM (Engine Control Module): While less likely, a malfunctioning ECM could send signals that cut the ignition. This is usually accompanied by other engine problems.
* Security System Issues: If your Malibu has an aftermarket or factory security system, a malfunction could be cutting power to the ignition.
Troubleshooting Steps (Proceed with caution, and disconnect the battery negative terminal if you're working on electrical components):
1. Check the Battery: Test the battery's voltage. A low voltage reading suggests a weak battery or charging system problem.
2. Inspect Wiring: Carefully examine the wiring harness connected to the ignition switch and surrounding areas for any visible damage, corrosion, or loose connections.
3. Try the Spare Key: If you have a spare key, try it. A faulty key could be interacting poorly with the ignition cylinder.
4. Wiggle the Steering Wheel: Gently move the steering wheel back and forth while trying to turn the key. If the ignition cuts out, it might indicate a problem in the steering column.
If you're not comfortable working on your car's electrical system, it's best to take it to a qualified mechanic. They have the tools and expertise to diagnose the problem accurately and perform the necessary repairs. Describing the exact circumstances under which the ignition turns off (e.g., while driving, at idle, only after starting, etc.) will be helpful to the mechanic.
