No air coming out of interior vents

[Teahead]

Anything in the engine compartment I can check before i tear apart my dash/heater box?

 

[Teahead]

WOndering if it's #9 here:

 

[wildphil]

One thing to check is the vacuum hose the goes from the inside of the vehicle through the firewall into the engine compartment. I can not remember where it connects for the vacuum source, hopefully someone will chime in with that info. Making sure it is still connected and that the hose does not have any leaks may save you taking anything apart. The hose going through the firewall is a hard plastic hose closer to the middle of the firewall if I remember correctly.

 

[wildphil]

You should be able to use one of those hand vacuum pumps from harbor freight at the actuator to test the operation of the blend doors through the actuator. But every time I had issues with the blend doors on a first gen s10 it was a vacuum leak. I would look into that first.

 

[Teahead]

I had two disconnected hoses in the engine compartment.

still didn't help the vent issue after connecting them.

took apart the controls.

stuck my thumb on the square hole on the back of that thing where all the hoses connect to it.

NOW WE GOT VENT AIR!

Hissing in that area led me to that culprit.

sucks now the part is NLA.

 

[Teahead]

part number 16047875 is nowhere to be had.

 

[Teahead]

another angle of the part

 

[wildphil]

I used to have a spare set of controls that included that part. I think that I sold it though. I will look and make sure. But pretty sure it is gone,

Edit: Ebay has an add for the whole control. It is a little pricy. https://www.ebay.com/itm/2668033727...KGHhBpoJdwOZkm+WYg2VNmdzk=|tkp:Bk9SR5b_go_uYw

 

[Teahead]

OK, I think I fixed it.

the vacuum thing splits easily in half. nothing holding it together until it's mounted on the panel.

after removing it and splitting it apart, I noticed one half is a labyrinth of raised rubber in a particular pattern. (wish I took a picture).

After trying a trick to compress the two halves together with a machine screw and lock nut, I took that off (since it didn't work) and I sprayed belt dressing in hopes it would swell the rubber labyrinth to reduce leaks from two halves together.

It seemed to work! Air now coming out of the vents!

probably years of that rubber labyrinth gotten flattened from use and age and was causing vacuum leaks out of sides.


piss poor design.

 

[Teahead]

I suggest anyone else having this issue of hissing out of that vacuum thing to take it off, spray some that will swell the rubber (I guess any petroleum product), clean it up, and try it out.

 

[Teahead]

actually a better fix is to run a machine screw w/a lock nut on it and tighten it down as much as you can while still being able to somewhat smoothly operate the lever for the HVAC position.