I had a strange thing happen to my temp gauge today... Just left the highway after 45 mins of stop the go traffic, All of the sudden my dashboard started "singing" an the display said eng temp high...I looked at the guage and the needle was all the way past H. In a panic I pulled over and immeditly turned on the heater. Within 1 second the needle drop halfway down to around I'd say 220(?) and the singing stoped....Anyone ever hear of this? There is no way turning on the heat could lower the temp that much in a split second. Think my themostat is going or is this electronical?