The rear actuator controls temp. You stated you had 115° at the vents. Does the temp drop when you dial the hvac temp control counterclockwise?

 

I have 115 at the center dash vents only. The outboard pair are 35 degrees cooler. If I switch to defrost, the air coming out of the defrost best
vents is 50deg at best....

As for the rear actuator controlling temp, the way I understand it thru alldata, both the forward and rear actuators are supposed to control temp. When I removed the rear actuator it had nothing behind it for the tip of the Actuator drive to fit into.

 

You didn't answer my question? DOES THE VENT TEMP DROP WHEN YOU ROTATE THE TEMP CONTROL?
The air inlet actuator valve (#4) should close when pressing the (air-recirculation) center button(pic above). There are 2 temp control actuators(#30) controls air output temp, and 1 mode actuator (#32) redirects air flow (pic above). You're having a 65°F DROP, from center vent to dash vent, doesn't add up? Air flows in the case, look at the right side of this pic (left side inside cabin) and you will see the air always flows to the windshield:

 

FYI, Just checked my '07 temp heat output <<center vent>>:
cold startup: 38°F at the vent
6minutes idling: 115°F at the vent
20 minutes idling and 1 beer later, thermostat opened@194°F: >>>180°F at the vent.

 

UPDATE,

Got the dash pulled and the air distribution box opened up. The door that is operated by the rear lower actuator broke the end post that actually attaches to the actuator drive spline and had fallen down into the box.

GM says the box is a "non serviceable part" and must be replaced as a complete unit. We were able to find 1 and have it on the way.

 

So you work on vehicles and have no idea what recalls are in play, whether they have been performed, or what effect they may have on what you are doing???????? So then you have no idea what you are doing, ie whether what you are attempting to fix is actually what needs fixin.

Oh boy.

Good luck.

 

Ok, now you're being a dick. We are a mom and pop shop, We don't have access to what recalls have actually been performed. All we have is alldata and the best I can do is read about any potential recalls and the problem we have narrowed it down to does not appear to be associated with any of the recalls posted in alldata.

You also could have simply said what recalls you were referring to rather than completely shred the fact that somebody doesn't know something that you might.

People come to these forums seeking help which is what i did and do not need some know it all ***** making things difficult

 

You came for information yet couldn't just answer a question X2?
Btw, blend door is designed to control heat/cool, NO DOOR=CONSTANT HEAT, which would be an issue when commanding a/c COOL. Go ahead and replace the "box", now knowing you have low vent heat temp. LIVE AND LEARN!

 

 

I understand the purpose of the blend doors. This thing has 2. Looking at it 1 appears to control the cold side air flow and the other controls the hot side....