having trouble on my 03 getting my heat from the floor and vent to the defrost. i turn the *** and it takes for ever to divert the flow to the defrost or sometimes in between any of them. the blower works great. any ideas why?

 

You have a vacuum problem. Check for leaks in the vacuum line and also verify that the check valve is working on the vacuum line going into the firewall.

 

i thought that. seems to have more of a problem in the colder weather. like this am. 0 here and it worked slow. warmed up a couple weeks ago and seemed to work better. i think!?

 

hmm. Sounds like you might have some moisture in there that could be freezing. I'm no expert on this subject so I don't know if it is even possible to get moisture in those vacuum lines. I know mine is slow but it is 11 years old and the dash has been out 2 times. I accidentally kinked the line the last time I put the dash back in. It has been slow ever since, but temp doesn't seem to be a factor on my truck.