Cannot change blower vents

[Shdwdrgn]

'97 Blazer seems to be stuck on the defrost setting all the time. Air blows out the top vent primarily, with a small amount coming out at the floor. When starting up on cold mornings, it feels like the AC blows for a brief time, which I was told is how the defrosted removes condensation off the windshield. Once the truck is warmed up, fan speed and temperature selector all work as expected, I simply cannot change where the air is blowing out from.

Any suggestions on where to start looking? Any fuses or vacuum lines I should be aware of?

 

[Me007gold]

'97 Blazer seems to be stuck on the defrost setting all the time. Air blows out the top vent primarily, with a small amount coming out at the floor. When starting up on cold mornings, it feels like the AC blows for a brief time, which I was told is how the defrosted removes condensation off the windshield. Once the truck is warmed up, fan speed and temperature selector all work as expected, I simply cannot change where the air is blowing out from.

Any suggestions on where to start looking? Any fuses or vacuum lines I should be aware of?

If it were a trailblazer I would suggest the mode actuator, do the s-10 blazers have the same set up?

 

[smitty5150]

I would start ny checking the vacuum lines. If they are ok, suspect is most likely the mode actuator.

 

[barron03]

On my 98 Jimmy it was a cracked line.

 

[Shdwdrgn]

I'm really hoping against the actuator, just because I've heard horror stories of what it takes to replace it...

As for vacuum lines - is this something I need to check inside the dash, or are there lines in the engine compartment that should be checked? Sorry, I've barely spent any time under the hood of this vehicle, so I don't have a clue where anything is on it yet.

 

[smitty5150]

The lines in the dash, not under the hood. Follow the procedure to remove the hvac controls. The mode actuator should be on the upper left side and the vac lines should be attached to it.

 

[Vicompc]

The HVAC accuator is very easy to change. I had to replace the one on my 95 Blazer, you just need to pull the dash and the hoses and actuator are on the back of the HVAC control head. See the picture of the part below

View attachment 17030

 

[Shdwdrgn]

You guys make it sound like its a piece of cake... As I said, I've never done any real work on this vehicle yet, so I don't know the first thing about pulling the dash apart. Anyone have some quick how-to links handy? If not, I'll hit up Google when I get time to look into the problem.

 

[tricguy007]

I'm going to bet it a cracked line under the hood there should be a black or grey vaccum line that comes through the fire wall that connects to the engine that will be your source vaccum for most of the hvac controls