Am looking to replace the AC vacuum actuator. My best guess is part # 15-72684. But I am not sure. It is the one with the yellow line that also actuates the slave actuator with the gray line.

If anyone has the actual part # that would be appreciated as well as perhaps a source for this. GM OE parts does not have it and looking at ebay and such, I don't trust my part #.

Thanks.


2001 3 button ZR2

 

This is my go to site for good exploded diagrams and part numbers. It always pays to double check the fitment by going to a GM parts website like GM Parts Giant and confirming the part will fit. Some will let you put in your VIN which helps with this.
https://nemigaparts.com/cat_spares/e...t/08/ts08-525/
I believe the slave door is identified as #5 in the diagram, p/n 52489533.






Trying to understand the HVAC routing has been a struggle of mine for a while. However, it has resulted in my accumulation of lots of diagrams which you might find useful.

The slave door has a grey hose going to it that is teed into the yellow one.



This is a picture of my slave door actuator looking through the glove box on my 99.

 

Thanks for all that. I have seen that diagram. Looking at the two on the left is what is confusing me. That would be 16 and 18. I need the one with the yellow and brown hoses that the gray slave line is also attached to.
My slave was not working at all and the AC actuator was sluggish. Appears to be a leaky diaphragm.
Also your link seems to be dead...

 

That is weird about the link not working. It just now worked for me. Anyway, I've attached a pdf of the whole page that also includes the part numbers and descriptions.

#16 is labeled as "Actuator, mode vlv(incls actuator, lever & spring)(acdelco #15-72684)"
#18 is labeled as "Actuator, defr vlv(acdelco #52470773)"
and
#5, the slave valve, is labeled as "Actuator, mixer vlv"

Last winter when trying to figure out if my slave valve was responsible for a vacuum leak, I disconnected the vacuum line to it and plugged it. I couldn't detect any difference in operation of the system. Of course I wasn't using the AC then. You might try just plugging the vacuum line to the slave actuator for now.

 

Again, thanks for all of that. I was floundering around on that site and found the same info but either the site or my computer is a bit wonky. A direct click would bring up an error code but a right click to open in a new tab seemed to work most of the time. I think that is what happened on your link.

I got my dash pretty well torn apart w/o actually dropping it. Working on the actuators (again), the fan motor problems and trying to squeeze in a new radio.

I was using a short piece of vacuum hose to do the 'inhale test" on all the lines. Everything was solid except the ac/heat yellow line which why I think the diaphragm is bad. I disconnected the 8 way vacuum connection behind the glove box where I did all the testing from and then each actuator on a weak line. I also dismantled the selector and cleaned it out which had an accumulation of fuzz and what may have been a past problem with ATF leakage. The lines were clear tho. The arm on the slave unit was also broken so I made a shop repair rather then spend another 20$.

I have other vehicles so the blazer can sit until I get it all done.

I actually ordered a GM resistor for the blower motor from amazon and they sent me a used one! The people who work returns can't be bothered to report a bad return and somebody pulled a fast one.

Cheers...