Searches on this forum have been a huge help so far. Thank you all in the past who have shared knowledge on this subject.

Here's what's going on: Air comes out of all vents, regardless of settings (moving the slider doesn't makes no difference).

I changed the check valve near the distributor (old one seemed plugged). No change.

Then I noticed that I couldn't blow through the little thin hard black hose that connects to the control valve (and goes down and disappears - this hose I believe is what goes to the HVAC inside). I suppose it's clogged and be the source of my problem?

In the car, passenger foot area near the tunnel, I see 2 small hard black hoses going into 2 other hoses(1 gray, 1 black, #5 and #6 as shown in Fig1B-9 C60 in the FSM). The gray and black hoses go into the HVAC unit (per the FSM) and I take it the 2 small black hoses work their way back to the little thin hard black hose near the distributor?

So just for a test: I hooked up a long vacuum hose and connected to the back of the control valve near the distributor (replacing the little thin hard black hose) and ran this hose over the windshied into the passenger side area and with some connectors and fittings I made up, I connected it to the 1 gray and 1 black hose. Started the car and the HVAC unit WORKED! I saw the defroster door open/close as it should, I heard the usually noises you should hear when moving the slider, etc...

So it sounds like my issue is with the little thin hard black hose from near the distributor to the passenger side foot area. What are my options here? I tried threading a thin wire through it from the distributor side - i can get about 28" in before it stops.

Anyone ever replace the little thin hard black hose? I heard it runs in with the main wiring harnesss? Do I need to get under the car? What about running a new line? Where would I enter the hose from the engine bay into the passenger side area?

Any help/suggestions/ideas are welcome!!

thanks!

Chris

 

Can't believe I posted this in the wrong section.

Moderator - can you please move to the C4 Tech/Performance section?

Sorry....

 

I've seen damage to the HVAC vacuum system, mice like to bite the vacuum lines.

 

FIXED.

After following the vacuum tube from behind the distributor, down to the starter and back up near the water shutoff valve, I noticed about an 1/8" section of the tube was melted. This is why the blow test (or others on here used smoke) failed when i tried to blow thru the tube. Once I cut out this section out and put in a new piece, all worked well.

Now the '84 has a full functioning HVAC system.

Next up: fix the sagging doors.