after market ac system

[GreaseDog]

That's hilarious...Our family had a 1978 Silverado with dash vents but no A/C and I found 3 trucks in salvage auctions this week with dash vents and no A/C.

dash pads are direct replacement, and will bolt right on. if you know anything about this era of trucks, you will also know that the dashes are notorious for cracking. considering the trucks you saw this week are at the minimum 20 years old, its highly likely the dash pads have been replaced. i can pull GM part numbers if you'd like...

just to eliminate any argument... which i know you will love to post...

here's factory GM parts manual's exploded view of the heater system...
1974-1978

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1979-1984

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notice the large Y shaped vent at the top of the illustration, that's the defroster duct that comes out at the base of the windshield. notice the lack of any sort of vent for the dash...

 

[GreaseDog]

Makes sense. You may not have needed a/c, but want to be able to put in on VENT and let in fresh air from outside.

then you open the vents in the kick panels... those are the little knobs by the lower corners of the dash.

 

[towman]

i would love to see a dash pad that covers the vent holes, thats just a trim piece

 

[89Suburban]

Just wanted to stick my bitch in about how the Y piece doesn't sit flush to the heater box outlet on my Burb and leaks a ton of air under the dash.

 

[RetroC10Sport]

The Silverado we had we'd known all it's life and the pad had never been changed. When the control was set on "VENT" it blew air out the dash vents.

 

[bucket]

The Silverado we had we'd known all it's life and the pad had never been changed. When the control was set on "VENT" it blew air out the dash vents.

Did it have the vents in the cluster surround too, or just the pad?

 

[RetroC10Sport]

Cluster bezel too. That was one very odd truck anyway.

 

[GreaseDog]

then its pretty apparent that what you're remembering is an AC truck...
non-AC trucks had a storage compartment above the heater controls like this:

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you say you remember switching the controls to the vent position? that's funny, someone erased the "VENT" option from all of my heater controls...
77

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80

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87

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and here's an overlay, which does not change the poistion or modes of the knobs, for an AC control(the lower, the upper is obviously the heat only control pictured above)...

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oh look... is that a VENT mode?

 

[RetroC10Sport]

Aw did I set you off door handle chromer?

Guess what, the truck never had A/C, factory or aftermarket. It had dash vents no matter what dissinfo from GM you post. GM books are NOTORIOUSLY wrong...Just like door handle chromers.

 

[GreaseDog]

look at your LMC catalog too. in the years i spent as a GM counterman, those books never once let me down.

please, do tell what the RPO code for this non-refrigerated air conditioning system is... GM info shows it, my own trucks show it, and the 50+ others i've stripped to the bones show it. i've shown proof that it doesn't exist... yet you continue to argue that it does. show me some sort of proof or documentation.