I was on my way home and turned the A/C on and noticed the temp gauge rising quickly, I shut the A/C off and the gauge went back to halfway but the digital gauge still said 233. Right before I got home I turned the A/C back on to see if it did it again and this time the gauge started rising and never stopped. It pegged and I got the overheating warning light and I coasted home for the last couple hundred yards. Any suggestions on what it is? The t-stat stop working maybe? HELP!