No rear heat on EXT

[zsiya]

2002 EXT Several months back (when it was hot) I had a leaking heater control valve replaced. Now, since the weather has turned cold, I have found that the rear heat isn't blowing hot. I have checked the actuators and they all function as intended. The coolant hoses under the truck in the rear are only warm-not hot. Is there a way to test the heater control valve? The front heat works great, but my kids are getting cold.....

 

[Mooseman]

Is the truck fully warmed up to temp when you checked how hot the hoses were? What do they feel like at the valve? Is the vacuum hose for it properly connected?

You could still have a dead vent temp actuator. If all else checks out, you'll have to pull the cover and check them. This thread has info on them:

2003 Trailblazer HVAC Schematic

I've got a 2003 TB EXT with the typical actuator clicking/non-functioning problems in the rear. I've removed the rear panel to access the actuators, and remembered an old site that had the hvac schematic and part numbers for this truck. I went to that "old" site, and saw that there were issues...

gmtnation.com

 

[zsiya]

Thanks for the link!

I checked the hoses after a 45-ish minute drive on the interstate. I didn't think to check the hoses at the valve. I assume both intake and output hoses? (only a part-time, shade-tree parts changer )