My 1998 V70 has about 240K on it and has developed a problem within the cabin vent and defrost air flow management. Its very definitely not a fan issue.

Mostly I get very low air flow through the vents, including the defrost vents. If I close all the vents except the center vent, the air flow is a little stronger, but if all are open, then a very light, diffuse air flow is what I get most of the time. However, on occasion, as if something had opened, I will get a big volume of air flow, but its usually last only a minute or so.

Could the problem be in the manual climate control head on my dash? Could it be the vent damper control motors? My understanding of the system is that there is no vacuum assist in this model, so I am supposing the problem is either mechanical or electric within the controller or damper motors? Anybody got any ideas? Thanks a bunch.