I had to replace the ignition switch last summer, and it had similar symptoms (About $400 including tow and new keys). It acted like a bad battery but that didnt fix the issue. Does your Bonne by any chance have the afternarket "ProLock" anittheft device installed by the original dealer? There would be a sticker on the driver'* side glass, and there would be a security device under the steering column in the car. From what I understand, these have been troublesome, too. I had mine disconnected and bypassed, since they are no longer supported.