Rear Heat Problem '05 LS Tahoe

[NAPOTS]

This is my first post here on this forum. A couple of months ago I bought a clean '05 LS 4x4 with the 4.8L. I have had to do a few small things to the truck. I am assuming this is normal wear and tear due to its age and the previous owner probably let a lot of them go. I had to replace the oil pressure sending unit, the transfer case encoder motor sensor and now my rear heat doesn't work. Normally I wouldn't care but my infant son gets cold back there. I have read a lot of threads that talk about replacing the rear climate control module and reference to a TSB that this is a common problem. I ordered the improved module off of Amazon and when I opened up my rear interior panel low and behold there is no module! I now gather that most of the posts were written in reference to the automatic climate control whereas I have the manual on my truck.

Do I need to replace the actuators? There are two of them. I didn't look when I had the rear panel off, are they both the same part and does anyone have the part number for them?

For reference I found this picture, this is not my truck but mine looked like this inside;

 

[JR79]

On my 05 Lt, both actuators are the same. First thing I would do is check hot water line with engine warm to make sure hot water is circulating to the heater core. If so, you can switch actuators to see if blend door actuator is bad (assuming other actuator functioning properly).

 

[NAPOTS]

It was working when I first bought the truck, I was hearing a clicking noise from the back of the cabin on startup though. Is checking the water lines for flow as simple as feeling that they are hot after the engine has been running?

I found this part on gmpartsdirect, part 8;
http://www.gmpartsdirect.com/auto-p...-engine/hvac-cat/auxiliary-heater-and-ac-****

Can anyone confirm that 89018356 is the part I want? It is only $37 on Amazon for an AC Delco. So order two to replace both?

Thanks

 

[JR79]

Yes, you can touch the water lines to confirm water circulation. Not sure about part numbers.

 

[NAPOTS]

No one on the part numbers?

 

[NAPOTS]

Well I for the actuators from amazon. It took about 20 minutes to get the rear interior panels off and swap the actuators out and put it back together. I did pull the fuse that controls the hvac out start the truck turn it off and put the fuse back. It seems to have corrected the problem