1. Key Issues:
* Key Fob Battery: Even if your Lumina doesn't have a remote keyless entry, the key itself might have a transponder chip inside that's powered by a small battery. A weak or dead battery in the key can prevent the system from recognizing it. Try a spare key if you have one. If it starts with the spare, replace the battery in your primary key.
* Key Programming: The Passlock system might have lost programming to the key. This is less common but possible. You might need to have your key reprogrammed at a locksmith or dealership.
2. Passlock System Issues:
* Passlock Module Failure: The Passlock module itself could be malfunctioning. This is a common cause. The module receives a signal from the key and grants permission to start the engine. A faulty module needs replacement.
* Wiring Problems: Check the wiring connected to the Passlock module. Look for any loose connections, broken wires, or corrosion. This requires some electrical knowledge and potentially a wiring diagram.
* Ignition Switch: While less common than the Passlock module, a faulty ignition switch could also interfere with the system.
3. Other Possibilities (Less Likely):
* Battery: While unlikely to be directly related to the security light, a weak battery can sometimes cause strange electrical issues, including starting problems. Check the battery voltage.
* Alternator: A failing alternator won't directly cause the security light, but a low charge can lead to erratic electrical behavior and starting problems.
Troubleshooting Steps:
1. Try a Spare Key: This is the quickest and easiest test.
2. Check the Battery Voltage: Use a voltmeter to ensure the battery has sufficient charge (should be around 12.6V).
3. Visual Inspection: Carefully examine the wiring harness around the steering column and the area where the Passlock module is located (often under the dashboard). Look for any obvious damage.
If you're not comfortable working with car electronics, it's best to take your Lumina to a qualified mechanic or an auto electrician. They have the tools and expertise to diagnose the problem accurately and safely. Trying to fix this yourself without the proper knowledge could cause further damage.
Remember to always disconnect the negative battery terminal before doing any work on the car's electrical system.
