I just had a stereo system installed in my 2002 xtreme and when he ran the power wire for my amp, he broke my dry rotted heater vacuum line. I replaced it and now it's only blowing hot air when I'm driving, and it blows cold air while I'm sitting at a light etc. what could be the cause of this? Everything worked perfectly until the vacuum line was replaced.

Any help would be greatly appreciated!

 

sounds like an inside vac line got knocked loose or there is an other leak..