Heat thru vents

[Boone83K10]

whatever flap/what I called a blend door... is behind 189, that's what I can see and am talking about. One way lets me see a "finned radiator" which I assume is the heater core, the other way I cant see anything. Is the rod from the mode or temp selector? Is the cable the mode or temp selector? The mode selector moves freely at the control head, the temp selector is very hard to move from hot to cold and vice versa. I didn't do the test you told me to do...

 

[Boone83K10]

Apparently I was seeing the "diverter valve" behind 189. it works fine.

my problem is the "temp valve"... from the service manual:

C60 A/C SYSTEM
Both the heating and cooling functions are performed
by this system. Air entering the vehicle must pass through
the cooling unit (evaporator) and through (or around) the
heating unit, in that order, and the system is referred to as a
"reheat" system.

Defroster and AC/HEAT valves are controlled by the mode selector. The temp valve is controlled by a cable from the temp selector.

see pic below.

 

[chengny]

At it's most basic, the problem comes down to this:

If you have the mode control set to VENT - with the temp set to cold - you can get full flow from the dash vents.

But, if you move the temperature control from cold to warm (without changing or touching the mode setting), the air flow from the dash vents drops to zero.

Correct?


If so, it must be that the temperature valve flap is somehow coming in contact with the valve right next to it - the one to the right if you look in the opening. Like this:

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[slowgo]

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.

Where do you buy the replacement plastic clips for the threaded rod + this is exactly what's wrong with mine

 

[chengny]

You might be able to buy the threaded piece, but I think the other one and the connecting rod are NLA everywhere. Junkyard item only.

GM Part Number: 1224062CONNECTOR, Air Distributor

http://www.gmpartsgiant.com/parts-list/1986-chevrolet-k20/a-c-heater-module-assembly.html


http://www.whiteracingproducts.com/...38_38846_38847_39109_39110&products_id=968360

http://www.gmpartseast.com/parts/gm-1224062_conn-pkg.html

 

[Boone83K10]

update:

I was driving the truck last night. If I am at high vacuum situation like maintaining speed, the heat coming through the floor on HEAT then I switch to VENT it will stay like that and blow hot until a low vacuum situation comes then it will go back to sounding like it is blowing out the back or just circulating inside the heater box.

this has me befuddled.

 

[Boone83K10]

I finally got around to looking at this again since winter is almost here in the mountains of NC.

All doors and actuators work great. Vacuum lines are good.

I was looking at the way the air travels when you select vent and heat...there is a lot of snaking in that box....less so when you have cold selected. All air passes through evap core but then has to be diverted 90 degrees to heater core then do a switchback to temp door. Another note is that the temp valve door has 4 cutouts on it.. when you have cold they are open plus the entire opening where the diverter valve is swung open to the evap core. When you have HOT selected, all air comes only through those 4 cutouts and the diverter valve covers the rest of the opening. This drops the amount of air allowed to come by that valve thus lower air speed.


I just chalk it up to that it wont blow as hard on heat as cold when coming out the vents...

 

[Boone83K10]

I dug into this again! I about froze the two mornings it was around 10 degrees and snowing. I finally figured it out. The gasket that is suppose to be at the vent distributor was gone along with the foam gasket at the top of the vent distributor. Got some foam out off one of those window kits and sealed that thing up! Heat is roasting me out of the cab and blowing hard out of the vents! Apparently it was keeping the under dash warm before instead of me!

 

[dguiley]

I had the opposite issue where most of my air came out the dash vents
and little on the floor or defrost. I opened things up and found the door pictures was stuck open, presumably because the little white bracket was broken. I reasoned since it was winter and my a.c. doesn't work that air out the dash vents wasn't necessary. Now My heater core developed a leak so I have things torn apart again. Just in case, I would like to replace this little white piece and get things working properly. Unfortunately I cannot make it out on the above diagrams. Can somebody please help me with what that part is called and where I can get it? Thanks so much

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[1987 GMC Jimmy]

I had the opposite issue where most of my air came out the dash vents
and little on the floor or defrost. I opened things up and found the door pictures was stuck open, presumably because the little white bracket was broken. I reasoned since it was winter and my a.c. doesn't work that air out the dash vents wasn't necessary. Now My heater core developed a leak so I have things torn apart again. Just in case, I would like to replace this little white piece and get things working properly. Unfortunately I cannot make it out on the above diagrams. Can somebody please help me with what that part is called and where I can get it? Thanks so much

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Factory PN is 3018715, but they have been discontinued. Classic Parts still carries a replacement, and their PN is 68-248. Hope this helps.

https://www.classicparts.com/mobile/1971-87-Diverter-Valve-Link-Connector-W-A_C/productinfo/68-248/

 

[yevgenievich]

That piece have also been replaced by others with various adapted versions from local hardware stores. Classic seem to be the only place that caries it in stock.