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Discussion Starter · #1 ·
So I have air blowing out of the vents no matter what setting its on. If i turn it to defrost there is little air that comes out under the windshield, but still a lot coming from the vents..

Is this common?

Does fixing it involve pulling the dash? (I hope not)
 

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i saw what you did there!
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check for vacuuum source to control panel from the intake manifold small black line hose under hood pass side through firewall
 

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Discussion Starter · #3 ·
check for vacuuum source to control panel from the intake manifold small black line hose under hood pass side through firewall
Thanks I will check for that.

I did do a search but I didnt think that would be my problem, guess I was wrong.
 

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Discussion Starter · #5 ·
So I looked under the hood today and couldn't find the vacuum hose.

My trucked is bagged on 20's with the stock heater still installed. I didn't build the truck, so I don't know all the stuff that was removed and such. Also I dont see a vacuum ball thingy that I believe these trucks have stock.

Any ideas on where I should check next?
 

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Discussion Starter · #6 ·
There is no vacuum coming from the "passenger" side of the firewall. Where about in this picture is there supposed to be one?



I took another closer look and did find this vacuum hose coming from the "middle" of the firewall and it goes into the intake manifold. Is this the one?



 

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Its on the driver's side. look for a "T" that goes into the fender, i can get a pic of it if you cant find it.

~edit~ found a pic on the forum. basically if that vac line is rotted out you will lose all control on the HVAC system, it would just blow out of the floor and defrost vents only.





Oh and reading your post again when you say "air blowing out of the vents no matter what setting its on" do you mean the blower motor wont stop, or just you cant control where the air blows? idk maybe its late and i am just reading it wrong.
 

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Discussion Starter · #8 ·
The air is blowing out of the vents no matter what setting its on. The motor does stop when it's set to off. I just can't get it to a specific setting, eg: defrost only, it's always coming through the vents.

It sucks because The whole truck was pretty much re-wired when it was built. So wires are not the colors or in locations they are supposed to be from the factory. Also I have custom fenders in, not the oem ones.

So since mine is doing the opposite, what could be the problem?

Sorry if I didn't make it clear in the first post.
 

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Didn't search very well....thread with same title!!
Anyway, this may help...... http://www.s10forum.com/forum/f137/heater-problem-456848/
Look at the parts diagram in the above link. #5, #16 and #18 are the actuators that control where your air flows. With the engine running, get your head on your gas pedal (that's fun) and watch #16 and #18 move as you turn the heat control knob from defrost to feet to vent (use a flashlight to keep your other hand busy ... lol). #18 will move when you change from feet to defrost. #16 will move when you "engage/disengage" the vent mode. #18 is actually lower than #16 when you look under your dash (not like the diagram). If the shafts from the actuators don't extend and retract, you have either a vacuum leak or a faulty actuator. #5 is the mixer valve actuator which I haven't watched in action because my passenger area is still full of parts that I removed getting to my defrost valve (which I ordered yesterday CatDaddy....$26)

Go to
http://www.gmpartsgiant.com/compone...-4wd~heater-asm-ts085250108-l35m30t10603.html
for the parts list and (until today!?!?) the diagram. You may have to "tweak" the options for your specific S10.

Hope this helps. If not, just ask because I'll be watching this forum until I get my heater assembly back together.

Rob
 

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Discussion Starter · #10 ·
Look at the parts diagram in the above link. #5, #16 and #18 are the actuators that control where your air flows. With the engine running, get your head on your gas pedal (that's fun) and watch #16 and #18 move as you turn the heat control knob from defrost to feet to vent (use a flashlight to keep your other hand busy ... lol). #18 will move when you change from feet to defrost. #16 will move when you "engage/disengage" the vent mode. #18 is actually lower than #16 when you look under your dash (not like the diagram). If the shafts from the actuators don't extend and retract, you have either a vacuum leak or a faulty actuator. #5 is the mixer valve actuator which I haven't watched in action because my passenger area is still full of parts that I removed getting to my defrost valve (which I ordered yesterday CatDaddy....$26)

Go to
http://www.gmpartsgiant.com/compone...-4wd~heater-asm-ts085250108-l35m30t10603.html
for the parts list and (until today!?!?) the diagram. You may have to "tweak" the options for your specific S10.

Hope this helps. If not, just ask because I'll be watching this forum until I get my heater assembly back together.

Rob
Ok thanks. I will go through the steps this weekend when I'm able to work on the truck.

Im afraid it's going to be a vacuum leak and not sure how I'll fix it because like I said everything was re done in the truck and the shit was probably removed. AC, cruise control, etc was all pulled out. Well see...
 

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I've got a similar problem. My heat will only come on through the vents and the defrost. Any setting that involves the floor will force air to the defrost. Fan speed is no problem, temperature is no problem, just no floor heat(it's been frigid temps here). I'm so glad I found this forum, didn't find much in any other searches.
 

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i have the same problem, popped the hood today, found the little T deal, its dry rotted but there is one hose that goes to nothing, its just open on the end. shouldnt that go somewhere? wouldnt that defeat the purpose of the vacuum hose lol?
 

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Its plugged into the fender, look in the pic i posted above.
 

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Hold on, let me get a pic. this is for 98+ only though.




under that bolt should be a nipple for the vac line. just feel around and you will find it.
 

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Great pix, beandip!!
BTW - your clutch m/c cover's lookin' kinda' grimy....we've come to expect better from you!!
 

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dont remind me :bawl:


but it is winter....though no snow..... flash makes it worse :D
 
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