Original thread led most to Blower regulator but the following additional tests and help from Gilly causes questions about "flaps" directing air for fresh air and recirculated air. '93 400sel with intermittent problems of air volume from vents...here the blower changing power when moving dial, etc...New test: upon start-up yesterday had great air volume in low, medium and high with AC, EC and recirculate. This morning had little to no volume upon start-up in AC, EC but still heard what appeared to be normal blower power noises from the dash consistent with the setting of low, medium or high. The recirculate seemed to produce a little more air volume from the vent and interestingly the EC air volume was no where near the outside temperature of 50 degrees....How do these "flaps" work, how many, could they be getting in the way of blower air??? DIY fix??