AC duct behind glove box

[Jaybird81]

1981 C10

Any know the diameter of the duct (behind glove box) that goes to the passenger side vent? #20 in photo. Mine is completely gone. Back order on LMC. New to forum. Got truck end last summer.

 

[Doppleganger]

I think I have #18 - can measure what it is. IIRC its a standard size - like 2" or so. I would bet Vintage Air knows - and probably carries something usable.

Plan B is checking with the other vendors. On the upside, LMC doesn't stay back ordered long.

 

[89Suburban]

1981 C10

Any know the diameter of the duct (behind glove box) that goes to the passenger side vent? #20 in photo. Mine is completely gone. Back order on LMC. New to forum. Got truck end last summer.

That truck is b*tchin man.

 

[DoubleDingo]

Have you looked at Brothers Trucks, or Classic Industries? There are other vendors than LMC truck

 

[Rusty Nail]

Tape measures are your friend but they don't do -ish for your post.count. huh??

 

[Jaybird81]

Anyone know what these “wires” are for? Behind glove box.

 

[Doppleganger]

Part of it almost looks like a cable for a blend door.

 

[Doppleganger]

IIRC someone here posted this awhile ago -

You must be registered for see images attach

 

[Old Guy Bill]

You sure it’s a wire and not a vacuum line?

 

[Jaybird81]

Could be a vacuum line. Not sure where it is suppose to go. Blend door is not functioning with controls

 

[Jaybird81]

Pretty sure black tube is a vacuum line. Not sure what the other one is and where suppose to go.

 

[PrairieDrifter]

That's all vacuum line. For the hvac

 

[75gmck25]

It’s all GM hard vacuum line, but someone repaired the end using a short section of rubber hose. It should have colored stripes that identify which vacuum motor each line connects to.
You can buy a roll of replacement hard line from Dorman, and most auto parts stores used to stock it in two sizes.

The T splice is because that vacuum line runs to the footwell vacuum motor you see in the picture, and also to the motor in the cowl vent. In Max A/C it opens the footwell vent to pull in air from the cab, and at the same time closes the cowl vent almost all the way, so you only get about 10% of the air from outside.

The heat blend door is controlled mechanically with a cable to the heat slider on the controls. Take off the vertical vent piece behind the glove box and you can reach into the plenum. If it’s never been apart you are likely to find many treasures that fell down the defroster vents (pencils, match books, bolts, business cards, etc.). That junk is what stops the blend door from moving.

 

[mlsceo]

1981 C10

Any know the diameter of the duct (behind glove box) that goes to the passenger side vent? #20 in photo. Mine is completely gone. Back order on LMC. New to forum. Got truck end last summer.

My truck is a 77. I just measured the duct at 3.5". Found it at Classic Industries, they are calling it 3.25" ID so looks like that's the one. Part# for 77 and 87 at LMC is the same. Classic sells 6' roll for $65, think I'll wait and let the A/C on that side blow out from under the dash till LMC has it back in stock for $20.

 

[Jaybird81]

Thanks for the info. Big help. What about this one also behind glove box?