hi.. i need some help please. i have a 1993 mercedes 300se and my interior heat wont work for nothing. i change the monovalve steel no heat. the blower motor works good. im very confused i do remember flushing my radiator about 4 months ago. do you guys think the flush could had something to do with my heat problem or what else should i check for next. and again thank you very much for your time and help.