1986 Heater Gears - yup --- GEARS!
 

I've got an '86 K5 with a heater assy that, with the Factory AC system appears to be much different from any other I've seen before ---> it has gears and vacuum servos that move the cylindrical divertors to mix, direct and change the airflow.

https://cimg8.ibsrv.net/gimg/blazerf...07fa30dc03.jpg
I painted it orange so I can find it in the snow bank....

The bad part is that when I did a heater core a while back I didn't mark the position of the gears so now I don't get flow to where the controls say the air is going.

This system does NOT use cables to move the divertors or mixing doors - just servos and gears.

Does anyone have an isometric chart with the timing marks explained to get these gears into the right position? Google has been ZERO HELP so far.

TIA. joe

Nobody?

Nope. No K5, sorry.

Might wait another bit, there are some guys who know their way around the K5's.
I would try and figure out who manufactured the HVAC and do searches on that assembly and not on the truck.

As far as I understand It could be relatively easy to get access to HVAC. Try figuring it out. Usually it comes down to logic and for the manufacturing they for sure had some means of identifying the positions. As you had it apart once a second time should be fairly easy - and take not where the things go.

I'm figuring a complete restoration at this time for a car that I didn't take apart. No pictures, no drawings or such. Just the parts catalog and couple of pictures of the same vehicle. Go figure is meant literally here.

How high are the snowbanks getting in your place? LOL

HVAC Gears..... Something Different!
 

The problem I have is .... was, really .... that I took the unit apart and tried to reassemble it while under the influence of legally prescribed .... er ..... medications.

Recognition and familiarity of the box may be rather hard to recollect, therefore. I DO remember even in my fog'd state was that there were no timing marks on any of the gears.... that's what confused me. Who puts a bunch of gears together with no reference points?

Also ... if memory serves me (and that probability is also questionable) ... the AC/Delco logo was on it....... or was it Harrison?

My money's on Harrison.

See what I'm up against here? Have a smidge of mercy on an old VietNam veteran ... emphasis on "old".

I'm not sure what to say about the gears side of things other than I hope that part got put bag together properly!

Here is what the factory service manual has to say about the hvac vacuum schematic & logic as to what ports will do what for any given mode:
https://cimg3.ibsrv.net/gimg/blazerf...17fb060ddd.png
1986 K5 HVAC Vac Schematic & Logic