New guy with a/c issues

[manfromthenasty]

Hey all, I recently came into possession of a 1978 gmc k15 with a 350 in it. It is a family truck, Granddad bought it new and I got it for graduating from college. Anyhow, the old guy got it in his head that the a/c wasn't working like he thought it should, so he opened the dash by way of the glove box, found some of the ducting to be old and full of holes, and ripped everything black and plastic out and dumped it on the garage floor. If one of you folks could post a few pics of a properly assembled under dash, it would be wonderful. My haynes manual doesn't cover this particular problem.

Not sure if imgur is welcome on this site, but this is the truck. http://imgur.com/a/Lkdvb

Thanks all.

[BADAZ chevy guy]

Welcome to the Forum.
I would go find a doner truck, or 5, from a junk yard and take a camera along.

[tucsonjwt]

Here is a link to a thread showing HVAC graphics:

http://67-72chevytrucks.com/vboard/s...=hvac+actuator

There was a thread on the complete ductwork and heater box R & R here on this forum somewhere, but I can't find it now. Maybe someone else can find it and post the link.

BTW - I have an 83 C20 beater with a dump conversion (Pierce Wrecker) - it looks like you have a better one - maybe Venco?

[manfromthenasty]

I have no idea the brand, I will have a closer look the next time I am under the hood.

[manfromthenasty]

Many thanks

[Eyegore]

I think lmc online catalog has a schematic

[79azc10]

I have a quick question the vacuum tank in the engine compartment has a line that goes inside the cab. Mine is missing and according to the above diagram is connects to a vacuum tee. Should that be a full vacuum source coming from the intake or some place else?

[4x4k30]

man that's a nice gmc just let me have it I can fix the a/c