I truly hope someone can give me some positive imput. I have a 97' E420 which has been in the shop 5 times with a/c problems. Intermittantly, one side or both sides of the system blows hot air while the center section cools. To date I have spent in excess of $1000 and I believe the service department erroneously replaced the blower motor, regulator and mounting plate. On the 3rd visit he added coolent and it brought the system to normal only to have it blow hot air within 20 minutes. For the next several days it has operated normally but still on occasion blows hot air. Living in Florida it is essential to have a/c for driving and I do not want to spend thousands $$ more to have parts replaced in hopes of curing the problem. Can anyone help me please? Thanks greatly!