weird AC question

Heres my dilemma:

My AC has been funky lately. It will only blow when I'm moving, but it will only work on the lowest setting. BUTTT also it will blow on the highest setting...and when it's on the highest setting it will also blow while i'm sitting still. It's the same for the heat too. it's kind of confusing...and i don't get why it's doing it. Anyone have any idea what i should check or what could be the problem?

Let me know if i need to clarify some things.

Thanks!

its a stock 99 auto

With the key on & the engine off, can you here the fan run on the lower speeds? If its only working in the high position, probably a bad resistor. Can be fixed for cheap if you do a search. Something about replacing the thermal fuse inside. I did this years ago on my old jeep-worked great.

Nope...can't hear the fan run on lower speeds with the engine off.

Another thing i forgot to mention is that when i turn the AC on...the electric fan still kicks in...but nothing comes out of the vents. just thought i'd add that.

thanks!

Ok, a/c off, heat off, fan works on what speeds? If it only works on HIGH you resistor pack is blown (the default is high, the resistors provide lower speeds).

There is a thermal fuse on the resistor pack that can be replaced by soldering in a Radio Shack part. Sorry, search to do that. Or get the resistor at a junk yard, if you know how to test with ohmeter. Or get an expensive new one.

Just fixed it. It was the resistor. Thanks for the help guys.