Hi, hopping someone can shed some light on a problem I have...

First off, my truck's an 89 blazer, 4.3L 4x4, No AC [:@]

When I first got the truck, the heater motor was siezed, so I went to a scrap yard and got another one.

Now the problem... The fan now works, and makes lots of "wind" noise... (I mean LOTS) but... nothing comes out any of the vents. Well, I shouldn't say nothing... if you put your hand up to the defrost vents, you can feel a TINY bit of air comming out, but hardly any. It doesn't seem to be blocked, as at highway speeds, with the fan off, just from the wind there is plenty of airflow... (basically only way my truck ever got warm last winter ) what's wierd is that at highway speeds, turning the fan on REDUCES the amount of air comming out. Also, the heater core works fine... what air that does come out comes out piping hot. I originally suspected I somehow got a fan that blows backwards, but that's not the case. I would really like to have some decent heat this winter... driving in the cold sucks.

Things I've checked...
-The intake for the heater fan is not blocked
-the route from the heater fan to the heater core is not blocked
-the heater core seems fine
-I'm assuming the door that diverts air to the heater core or around it works fine, as the heat control works fine

Things I'm not sure of...
-the air flaps that direct air to the different vents... don't think they work as the vent selector doesn't do much to the airflow at highway speeds, however, as air comes out the defrost, I'd think that with the fan on, air should come out of the defrost no?

I'd rather not rip apart the dash... it's rather old and "brittle" so I'm afraid that if I take it apart, it isn't going to go back together if you know what I mean...

 

See the other post in this forum about vents. She is haveing a similar problem, and the answer to your question is there. At least a start to solve the problem is there.