Well, my understanding is if you remove the actuators, you should have something sticking out that you can manually turn to move the internal dampers and doors. Have you tried that?

If things stay hot, sounds like the blend door actuator is not really working. Does the mode actuator switch from floor to vents to defrost openings? The linkages or stuff inside the air box could be messed up? I've seen folks remove the bottom of the box, and drop it off, to get inside there, without removing the entire dash.

I don't see the 3rd actuator you mention on the diagrams above, but do know that on my Silverado and my C1500, the recirc door opens over somewhere near the blower motor, to allow it to suck in cabin air instead of outside air.

 

Thanks, I'm going to try and remove the blend door actuator today. I haven't tried moving the linkages manually. I'm hoping to chat with a chevy tech today about this. I will check the mode operation again today, but I believe that it was working.

 

So, I realized that the mode actuator wasn't working either and decided to pull that out to check the door and linkage. It appears that the linkage on the left has come off and I can't figure out where it reattaches.........I'll probably move on to the blend door next since that was my original problem.

 

If it is your mode door Blend Door USA may be able to help

 

Ok, I've replaced the blend door actuator and the recirculating door actuator (that one was bitch). I'm still getting warm air from the front and cold from the back. The heat control appears to be working correctly since it does get hotter when adjusted. The mode actuator appeared to be functioning properly and moving the linkage. Unfortunately, one of the two linkages has become disconnected from whatever door it was attached to. I opened the two old actuators to find cracked main gears.

Two questions; where does the rear linkage for the mode actuator reattach? And, would that affect temp?..........seems unlikely.

Thanks for the input!

 

Greetings, it sounds like you are either not getting hot water to the rear, or the rear heater coil is plugged.
If the proper level of corrosion inhibitor has not been maintained in the engine cooling system, you very likely have corrosion in the auxiliary heater pipe. When this happens, corrosion products will spall and plug the very small orifice in the supply line to the rear heater. You may be able to flush the obstruction out. If it is corroded beyond repair, I believe that this part is now obsolete and will have to be obtained from an auto recycling yard. (Part no. 15960693 Pipe)

If you are lucky and only have a plugged heater coil, you should be good to go by back-flushing it using the supply and return lines under the hood.
Hope this helps.
Jack

PS the front dampers have no effect on the back of the bus.

 

Thanks so much Jack, I suppose I should have explained the entire issue. I get great cold air in the rear, but only warm air in the front. I assumed it was the mode door and the linkage doesn't make sense. It appears that part of the linkage for the mode door has become unattached and I can't determine where it goes.

Ron

 

You could have a bad blend door or maybe just the driver itself which is not allowing the heat to flow to the back of vehicle. Blend Door USA may be able to help if it is in fact the door. You can also reach out thru the website, and we can assist you in trouble shooting the issue.