Hello, I have a 1999 E300 TD, a couple weeks ago the AC quit working. Today I took it to the local dealer and had them diagnoise the problem. After a check of the system I was told it had a bad evaporator Temp. sensor. I had this replaced. After paying a $400.00 dollar bill I left the dealer with very cold air conditioning, after driving about 8 miles the air began getting warmer and the little red light in the EC button came on, it can not be turned off and have no more air conditioning.Any ideas would be appreciated.

Regards, Larry G