2001 Explorer Hazard Lights and Radio Continuously Flash

I have a 2001 Ford Explorer Sport which was purchased used. Its had electrical issues since I got it, but at first it was minor issues; such as, the check engine light remaining on, and the over-drive light will begin to flash sometimes while I am driving. The past two days in a row, after cutting my car off, I would return and the battery would be completely dead. I never left any electrical components on, so Im not quite positive what caused the battery to die. My grandfather wanted to clean my battery cable connections, thinking battery corrosion could be the problem. After disconnecting my cables, cleaning, and reconnecting them, I turned on my car and the radio and compass/outside tempurature display both began to flash on and off. The hazard lights also flash with them, along with the clicking noise that they make in the dash. It will flash for about 30 seconds and stop for about 10, then start again. This continues until I turn my car off, and starts again when I turn it back on. Please help and thank you for your time.