Aryonas

Hi. The daytime running lights on my 2000 mustang are flashing, seemingly on and off, constantly. You couold say they are blinking, constantly. When I turn on the headlights it will stop for a while, then start again. Now it has gotten to the point that even when my high beams are on they will blink after a while. Obviously when this first started happening it would stop if I turned on the headlights. But now that does not fix it. What is causing this? Can if fix it in my garage? I was wondering if it was one of the following: Relay, breaker behind switch, bad wire, shorting wire, bad switch. Thanks very much.