I noticed, just recently, when running the Air Conditioning (any of the AC modes) that the top vent quits working (I don't know if this includes the windshield defogger) and all the air is directed to the lower vents. This happens after the AC has been running for awhile, and will come back on after sometimes 20-30 minutes...What's up with this?
When I worked with Honda, some of the earlier cars had a vacuum switch that controlled the vents, and when it developed a crack,it would loose vacuum with similar results.
This seems to be a somewhat common problem (I've searched the forum and followed some of their suggestions). I've checked under the hood, and all the lines look ok (and I've sprayed with carb cleaner and had no change in idle speed). This leads me to think it's under the dash...any suggestions on what to look at?
I also had an engine problem, at the same time I first noticed this vent control problem. It was very hot (90+) and the engine had started rough, seemed to clean out and run ok, and than, as I was driving, it would loose power and die (or start to die). This happened 3 or 4 times before we got back to our camp and didn't trigger the check engine light. This hasn't happened again, but the vents are still a problem. Maybe it's related, or, maybe not...
Any help would be appreciated...