* Dead Key Fob Battery: This is the most frequent cause. Replace the battery in your key fob. If you have multiple fobs, try them all.
* Key Fob Programming Issue: Sometimes the key fob gets out of sync with the car's system. You might need to reprogram it. This usually involves a specific sequence of steps involving the ignition and the key fob buttons. Consult your owner's manual for the precise procedure. If you don't have the manual, you can often find a digital copy online by searching "[Year] Buick Riviera owner's manual PDF."
* Faulty Security System Module: If replacing the battery and reprogramming the fob don't work, the problem might lie within the car's security system module itself. This requires professional diagnosis and potentially replacement by a qualified mechanic or an auto electrician experienced with older vehicles.
* Alarm Triggered by Accidental Activation: Sometimes, the alarm might be triggered accidentally (e.g., by a bump or a short circuit). Disconnecting the negative battery terminal for a few minutes might reset it, but this will also erase any settings related to the radio and other electronic systems. You will have to reprogram your radio code.
Important Steps to Try:
1. Check the Owner's Manual: This is your first and best resource. It will provide specific instructions for your car's security system.
2. Replace the Key Fob Battery: This is the easiest and most likely solution.
3. Try the Spare Key Fob (if you have one): If you have a second key fob, try using that to see if the problem is with the key fob itself.
4. Disconnecting the Battery (Last Resort): Disconnect the negative battery terminal for about 15-20 minutes. Reconnect it and try to start the car. Remember, this will erase some settings.
If none of these steps work, you'll need to seek professional help from a mechanic or auto electrician specializing in older vehicles. They have the tools and expertise to diagnose and repair more complex security system issues. Mentioning the specific symptoms (e.g., "car won't start," "alarm keeps going off," etc.) will help them troubleshoot effectively.
