Defrost trouble

[Dylan88]

Hi question

88 Chevy Silverado. My defrost isn't blowing but everything else switches and works. I'm wondering where the defrost door is? Any ideas what i could try? The actuator by the gas pedal seems to be moving and tried to lube it best I could. Maybe it's still faulty ?

 

[Donald Mitchell]

That's the one, most likely the foam seals where case and the defrost vents meet has deteriorated and is just letting the air blow out. this is after I replaced the foam weatherstrip on the case.

 

[Dylan88]

Ok does whole dash need to come out or any other ways?

 

[Dylan88]

Is there a flap or defrost door that could be stuck? Its blowing out floor when set to defrost. Vents will switch and work normally

 

[Dylan88]

Sorry not best photo. I noticed the one silver peice I circled in red doesn't move but the other one does. The mechanism seems to be working. Could that be why or does that side not move ?

 

[east302]

Watch the notched silver dial as the air is adjusted from panel to floor to defrost. It will (roughly) turn between the two outer marks on the actuator.

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Assuming it does that, how do the linkage arms respond - is that one linkage moving but the silver arm not turning? That arm is connected to the damper shaft.

Dash needs to come out to get to that damper. In Donald’s photo, it’s in the thinner slot closest to the firewall.

Does it leak air at the floor when set to dash/panel? The floor damper has a rubber seal along the perimeter and tends to rot, leaking air. You can see it by pulling the floor outlet cover.

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[Dylan88]

The one silver arm i had circled isn't moving . Was told it was the defrost flap?

 

[Dylan88]

Mine has the circle you mentioned right in the middle it doesn't move but the arms are. Just that silver lever at the top seems stuck?

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[east302]

So the notched dial doesn’t rotate at all?

The center (12 o’clock) is the floor setting with the 1 and 11 o’clock marks being panel and defrost but I forget which is which.

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The defrost damper is the one closest to the firewall on the left below:

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[Dylan88]

That how mine looks