may not be an answer but I have he same problem - I changed the water pump last fall and now all I get is cold air out the back but the front heater is hot - is therea petcock? I even had a GM dealer tell me there was a circulating electrical pump under the van but I did not see it - mine also seems to have cold lines leading to it when looking up from the bottom.
Bob
December 2007
howtomendit.com for free repair help, information and advice.
