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86 k5 heater controls emergency

Justin Fleming

Justin Fleming

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Hello all, Lets see how technology helps me today in the blizzard!!

I am out plowing in the k5 and for some reason the air is not coming out at the front window when the defroster is selected. I notice it seem as if the lever moves real freely, however it does make some changes and shut off when put in the off position. So what I have done is poped down the glove box and I can position the lover for the heat/cool and I found a lever to minipulate that makes more air blow at the window. The problem is that most of the volume is being blown at my feet and I really need it on the window..

Any quick fixes....

thanks
 
Directly behind the glove box is some of the manual controls for the air director, but, I think the one your after is vacumm controlled.
 
Not going to help much in a hurry, but the air divertor door has a two way vacuum motor mounted behind the box. You can see it with a mirroe, but that's about all. I'm going to bet the little plastic connector on the door broke and the motor can't push it.
 
If your truck is like my 91 there is a diverter valve just behind the glove box door which is controlled by a vacuum actuator. If the actuator is shot, you can probably remove the threaded rod and move the door manually. In this photo it's the rod with the white fitting in the front:

uqzh9l.jpg
 
Jessie James said:
If your truck is like my 91 there is a diverter valve just behind the glove box door which is controlled by a vacuum actuator. If the actuator is shot, you can probably remove the threaded rod and move the door manually. In this photo it's the rod with the white fitting in the front:

uqzh9l.jpg
Click to expand...


I belive the other end of that rod is connected to the door that is vacuum operated.
 
On my 86 the plastic box had a hole in it where it had been kicked....My a.c & defroster were working, it just wasn't making it to the vents....:doah:
 
on the left side of Jesse's picture is a plenum thing that comes off with 3 bolts. take it off and look at the door in it. there is a piece of shyt plastic connector that may be broken....
 
British Slave said:
That's it.
Click to expand...

I just replaced mine yesterday and now it works like a charm!

Before buttoning up the cover, I played with the controller to see what that door actually did. Before, the door would move around but would not close all the way. Now, with the new ($2) piece of plastic, it opens and closes all the way and runs smoothly.

Took a little exploring and driving to two chevy dealers but found the part. My local one had 3 others and I was temped to buy them all but decided just one for now.

If anyone wants one, let me know and I could pick one up and probably ship it for $0.50 or so.

Be sure the back lip is behind the door before screwing it down. You may have to play with the control to get the arm to move to the "open" position. It made it easer for me.

Good luck!

All my vents, heater and defrost blow good and strong now.:woot:
 
I had a double problem with my defrost-heater-A/C. No matter what I tried, when I had it in A/C or defrost most of the air came out on the floor. Evidently the previous owner had a heater core installed and who ever did it got the vacuum lines reversed on the double action motor behind the box. I took a short cut and just cut and spliced the vacuum hoses in the dash. Now I got air out the right places. Also found that little plastic clip broken. I have a complete A/C heater from another truck and the clip was good on it. Now every thing works.
 
Jessie James said:
If your truck is like my 91 there is a diverter valve just behind the glove box door which is controlled by a vacuum actuator. If the actuator is shot, you can probably remove the threaded rod and move the door manually. In this photo it's the rod with the white fitting in the front:

uqzh9l.jpg
Click to expand...
I just did my heater core a week ago and ran into a similar issue; this air diverter that's attached to the vacuum actuator is indexed by a keyed ear on the bottom to which the shaft goes through to keep it stationary on the shaft. That keyed ear will round out over time thus making the diverter useless, as it spins freely when the shaft turns. I also found that the way in which the diverter itself is indexed within the box has a lot of play, and when the vacuum actuated rod is pushing the diverter, it can cause it to jump out the index and bind.

If you remove the ducting that bolts up right in front there, it will expose the blend door. With the blend door open, you can see the diverter and it's position. You can fix the play on the diverter by making a sort of shim to stick in between the outer and inner sections of the heater box (the interior box is actually two parts to hold the internals and the heater core), where the diverter sits. I used the tapered end of a zip tie; sounds like a cheap fix, but it works, and works damn well. You can also pull the rod straight up and out of the bottom of the keyed diverter ear if it's rounded out, and use some epoxy in there to keep it in check with the rod.

Hard to explain, probably hard to understand unless you've got the heater box in front of you, but when I fixed this my heat/AC was working wonderfully out defrost/vents/floor.
 
Yo said:
I just did my heater core a week ago and ran into a similar issue; this air diverter that's attached to the vacuum actuator is indexed by a keyed ear on the bottom to which the shaft goes through to keep it stationary on the shaft. That keyed ear will round out over time thus making the diverter useless, as it spins freely when the shaft turns. I also found that the way in which the diverter itself is indexed within the box has a lot of play, and when the vacuum actuated rod is pushing the diverter, it can cause it to jump out the index and bind.

If you remove the ducting that bolts up right in front there, it will expose the blend door. With the blend door open, you can see the diverter and it's position. You can fix the play on the diverter by making a sort of shim to stick in between the outer and inner sections of the heater box (the interior box is actually two parts to hold the internals and the heater core), where the diverter sits. I used the tapered end of a zip tie; sounds like a cheap fix, but it works, and works damn well. You can also pull the rod straight up and out of the bottom of the keyed diverter ear if it's rounded out, and use some epoxy in there to keep it in check with the rod.

Hard to explain, probably hard to understand unless you've got the heater box in front of you, but when I fixed this my heat/AC was working wonderfully out defrost/vents/floor.
Click to expand...

I know exactly what you are saying. Mine spins on the shaft also. I thought about a drop of epoxy at the bottome where the shaft goes thru. I have a new one, but I don't feel it's worth the efort right now to install it.
 
It's a PIA, that's for sure.

I had no idea where to purchase a new one anyway, so I had to improvise.

Where can one find small internal parts like that?
 
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