My a/c stopped today. Everything was fine until I switched over to defrost. Then switched back to low cool. Would not blow cold. Next day only defrost comes on. No other switches activate anything. I have read up on the forum but everybody has a little different problem than I seem to have. I checked fuse. Is this the CCU contact points failing? Maybe need new CCU (junkyard) THanks in advance for responses. I truly enjoy this forum. 1980 300D.