97 c230 ignition help
 

I've had my 97 c230 for about 5 years now. It's begun making a repetitive beeping noise whenever the car is moving fast enough (about 3 mph or more) forward or backward. It gets very annoying while driving. It sounds like the beeps when you leave the key in the ignition or the lights on and open the door but the door is closed. I was told to spray WD40 in the ignition and move the key in and out. But it's been over a week now and nothing. Any help?