Fresh Air vents with factory A/C?

[Silver Square]

I've got a 1977 Sierra Grande with factory A/C. Is there supposed to be a fresh air vent assembly on the passenger side on this truck? Can't seem to find any solid info on this. I'm seeing the valve assembly on LMC and USA1, but I can't seem to find the pull handle that would open/close it. I can only find that for non a/c trucks for the driver side. Is it the same part? Is there any place to get this? My truck came with aftermarket speaker kick panels, so I have nothing to use as a point of reference. Can someone post a picture of this area on their '77? Thanks.

Also, is it possible to put the fresh air vent on the driver side? Is it just a matter of getting a non a/c kick panel assembly, or will I need to do more modifications to get it to work?

 

[Old Guy Bill]

A/C trucks were vacuum controlled by Heat/A/C controls, non A/C trucks got a pull handle. No drivers side vent.
LMCs site under “Interior Panels”

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[75gmck25]

The A/C trucks defaulted to having the kick panel vent closed (it is spring loaded), and the HVAC drew fresh air in from the cowl above and fed it to the blower motor. The kick panel was not designed to provide direct fresh air like a non A/C truck.

When the A/C is in max/recirculate mode, it applies vacuum to two vacuum motors. One in the kick panel opens and starts drawing in air from the “cabin”. The one in the cowl closes almost all the way, and reduces the intake of fresh air to near zero. Up behind the glove compartment, on top of the HVAC plenum, there should be a vacuum line with a T, and it connects to the two recirculate mode motors.

 

[Old Guy Bill]

This is a ‘78… with a non-A/C kick panel installed. It is an A/C truck but the original system was trashed so it got Vintage Air. Instead of blocking the vent I installed the manual vent.

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[Silver Square]

Thanks for the info folks, that explains why I can't find the pull handle for it lol. I never thought it might be operated by the HVAC panel. I hope my truck still has the plenum and related bits to make it work, I see it's grayed out on LMC. That'll be fun to track down. I'll have to check when I get the truck back, it's in the shop getting some work done now.

 

[Silver Square]

This is a ‘78… with a non-A/C kick panel installed. It is an A/C truck but the original system was trashed so it got Vintage Air. Instead of blocking the vent I installed the manual vent.

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Were you able to put the manual vent on the driver side too? Curious if that's possible on the a/c trucks. My old Dodge has one, and it's really nice, I use it all the time. It lets in a LOT of air. I like windows down cruising unless it's absolutely miserable out.

 

[Old Guy Bill]

There is no drivers vent in that era of trucks, no hole, no room due to the parking brake.

 

[emoze]

on my '84 i installed old manual vents on both sides with junkyard parts

 

[EvilGenius]

The sheet metal is not provisioned for vents on the driver side in AC trucks. They never punched the hole.

In heat only trucks there are two versions of trim for the kick panel. The common option is trim just around the vent hole with the manual handle. For the rare Silverado trims with heat only there are ones that go the full height from the vent hole down to the floor. Passenger sides of this are easy to find because it's the same as the AC trim. Driver side is hard to find. I found a set on ebay when I was looking. It's really hard to pull the hood release as it's in the same area as the vent handle.

AC trucks have only one version of vent trim to my knowledge.

 

[AuroraGirl]

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heres an exposed cab with the dash out of the way if it helps anyone