Rear Fog Light on 2004 Volvo S40

The rear fog light goes on and off by itself. Some days it will be fine and stay off, but on other days it will turn on by itself so I'll turn it off but 2 mins later it just turns on again. Sometimes it gets so bad that it'll rapidly just go on and off for a few mins. Any idea what might be wrong?

Asked by for the 2004 Volvo S40
Did you ever get this issue resolved?
No, I still haven't. I just took out the light bulb for now. Any help is appreciated. Thanks.