2007 Chevrolet Uplander Q&A
2007 Chevrolet Uplander Question: Heater will not blow warm air when car is stopped or parked, but will when moving.
Check your engine coolant level, it's probably low. Your heater core uses the heat off of your engine provided by your engine coolant. - mrtrans
Sounds like you are low on antifreeze. If the level is low, the car does blow cold when the car is idling. Most likely this is an inexpensive fix that should remedy your problem. - Visitor