For some reason my front is blowing hot and the rear is blowing cold. IT does not matter what I set my temp control. Also it can be set to fan and it blows hot. Just started doing this and have not had any problems until now.

99 Expy 307K miles

 

Your blend door is probably broken (very common problem on 97-02) and stuck in the hot position. The blend door actuating motor could be bad too, but I haven't seen one of those go bad yet.

 

just got blend door fixed today... exact same problem as you... expect to pay around 600-900 for labor and parts... the whole dash has to come out

 

Thanks but for that price I will pull it myself.

Another of the symptons is that is does it intermitantly. When you first turn it on it will blow cold then you hear the blend door shut. And other times it will stay blowing cold.

 

There are instructions for F-150 which is very similar. Takes close to 10 hours. Don't lose any bolts/screws....