Buick Repair Questions? Ask a Mechanic for Answers ASAP
Hello, my name is***** to hear about your Buick. Most of the time this is caused by a failing ignition switch. This is a very common problem on this vehicle that causes this. It can also be the body control module or the fuse box, but those are not nearly as common as the switch. The switch fails internally and causes this. It can be hard to diagnose since it does not happen all of the time. I usually do a voltage drop test on it first and then replace it as the first step if the issue cannot be recreated. I hope this helps. Please let me know if you need further assistance.
The alternator would not do this off and on, and if it did the battery would be dead. As for the anti theft system, there are bypass kits that you can get online, but there is no simple way of doing this.