The car is a 1979 300SD with a 160,000 miles and lives in New York City. I have posted a few threads about all the problems I have been having with my new Bosch blower motor. The #3 fuse (blue 25A) will not stop poping when I hit any of the ACC buttons. I went to an electric guru who got it running and told me my blower motor was no good(worked just fine with a patch power cord right to the blower). The a/c worked for about a week on low only after I left his shop. Today the fuse starting poping again. The weird thing is when I put a new fuse in the only thing that works is the defrost. The fuse pops but the defrost keeps blowing even though I see the fuse is broken. Can someone explain this to me??? I know that when the servo goes bad the only mode that works is defrost. I do not believe my servo is bad as it was replaced by the previous owner. I am guessing that maybe my control panel is messed up and needs to be fixed. I know these are repairable. Is there a relay or voltage regulator or something that I am missing here? Has anybody else had this similiar problem in there car? By the way the horn went dead as well. Although today it worked very faintly. Are these related? Please fellas I need your help. This is the last straw. If I can not get the a/c working for a NYC summer the car is history!!!