A little recent history for my 1990TE. Last fall, had a slight coolant leak from water pump area. Took it to a fairly good indie, and he said that an additive may resolve issue. I agreed, and needless to say, it was a failure. New water pump, new radiator, new idler assembly and belt installed and cooling was great and no leaks. Unfortunately, no heat either. Removed plunger from monovalve and heat restored for winter, unregulated, but tolerable. Plunger installed this Spring and heat shut off, which is OK for summer use. Installed new monovalve recently, and still no heat. Have 12V between 2 terminals on monovalve plug with key on and in heat mode. While driving, I played with temp control knob stop to stop several times and heat came on. None next day, went to defrost, heat on, then off in reg mode and defrost mode. Think I should belooking at reman CCU? Also, noticed in auto EC mode, blower fan kicks on well before car actually warms up. Sorry about long post, but I need to get this resolved before really cold weather kicks in.