a/c ?'s
 

hi, am installing a/c for the first time in my 73gmc non-air. i've removed the interior box with the heater core which is new. removed the blower fan and saved it. installed 3 pieces of a/c tubing under the dash. the tubes go to 3 outllet vents- 2 in the dash bezel and 1 above the ash tray and 1 on the pass side of dash. i have to find a dash bezel for the latter two. 1 piece of tubing has a rectangular opening that is located slightly below the glove box on left side. Does the blower fan get installed through the firewall and where. i think this fan is a/c heat/ combo. the tubes came from a parts yard, 81 chevy subn. all in very good shape. the evaporator, where does it get mounted on the firewall. i do have a a/v heater module with small vaccum hoses. they get attached to the evaporators on the kick panels, the other hose i don't know. i have the old air vent style kick panels saved. will send pics to help. thanks :gmc2:

Re: a/c ?'s
 

It sound like you are converting a non-a/c truck to an a/c truck using all factory parts. The firewall on an a/c truck has different cutouts than a non-a/c truck. You will need to modify your firewall.

Re: a/c ?'s
 

j knight, thanks for the response. that's correct, a conversion. out here in AZ you need AIR. i would like to do the interior first, get all the necessary parts from a recycle yard. iv'e seen some good interior a/c parts there. customizing the fire wall is no problem. i just need to know where the parts are attached on the firewall ie Evaporator, blower fan. Do i have to change the heater core? the defroster tubes are in their normal location but somewhere on the tube on the bottom has to be connected to the a/c hookup. i have attached some pics to see. thanks again. joeyt:gmc2:

Re: a/c ?'s
 

Here is a pic of an a/c firewall. You will need EVERYTHING inside and outside the firewall. I don't think anything is compatible from the non a/c parts to the a/c parts except "maybe" the blower motor.

http://www.vettemod.com/forum/imageh...8478266f8b.jpg

Re: a/c ?'s
 

j knight, lost text after "maybe. do i keep the defrost tube setup? Is the heater core different from the other heater core? what are the 2 holes to the right of the rectangular hole in the firewall? are there any cab pics of the a/c interior parts thanks for any help

Re: a/c ?'s
 

I don't know if the defrost tubes are the same but I would guess that they are the same. The heater cores are different. As far as the two holes, the one on the left is for the wire harness to pass through that goes to the blower motor, resistor, low pressure switch, and the vacuum tube to the a/c blend door controls. The one on the right should be for the electronic spark control for the distributor.

If it were me wanting a/c in a non-a/c truck, I would go with a complete bolt in Vintage Air system. ($1300)

Re: a/c ?'s
 

Here is a pic of the two different blower motor boxes that are in the engine compartment. The heater core holes are in a different location and the cores are different. The non A/C heater cores are larger.Attachment 1295178
a/c on left. Non a/c on right.

There are other items to address during the conversion. The manual vent in the kick panel on the passenger side gets replaced with a actuator controlled one. And there is an additional actuator inside the rain gutter on the passenger side.

Re: a/c ?'s
 

silverbear thanks for pics and advice. do i use the kick panel vent housing for the actuators? i saved it. i have these vaccum small hoses on he back of the a/c control module. where do they go to? thanks for any help joeyt

Re: a/c ?'s
 

They are different. I have both types out in the barn. I will try to take some pics of them tomorrow. I will also get pics of the other component that are different.

Re: a/c ?'s
 

A few pic of the differences between the A/C and non A/C components.
Attachment 1295347

Attachment 1295348

Attachment 1295349

The defrost ducts are the same and connect to either box the same. You can either keep the manual kick vent and block off that vacuum port or add in the actuator controlled vent. I would recommend physically looking at a truck with the A/C setup to see how things are routed and what you like and don/t like about the factory setup.

Re: a/c ?'s
 

silverbear, thanks for the pics, found some trucks with parts i need. thanks for the help. you guys are topnotch. will show you the results when finished.

Re: a/c ?'s
 

Silverbear finally have most of the interior a/c parts installed. Looking at your pic with 2 types of covers, i need the one on the left, the a/c evaporator cover. My question is does the a/c motor get attached to this cover? If so, what cage do i use? The space is too small for the cage that came with the motor. Also do i have to make a bigger hole for the motor and cage? How does the evaporator get attached to firewall, does it get connected to evaporator cover? Thanks for any help frankyjoet :gmc2:

Re: a/c ?'s
 

Yes the blower motor will mount to the cover. I can't recall off the top of my head how the evaporator core mounts into the housing except that the dryer canister mounts to the evaporator and the canister mounts to the cover. The cover mounts to the fire wall using the through bolts from the inside air box. Here are a few pictures for reference.

Attachment 1495728

Attachment 1495729

Attachment 1495730

Re: a/c ?'s
 

silverbear, here are some pics of the firewall before and after customizing. Note the blower motor is attached temporarily to the firewallwithout the cage. when i get the housing from a bone yard, i'll take that off and attach it to the housing. have a ?, are the evaporator housings interchangeable from the 70's to 80's? :gmc2:

Re: a/c ?'s
 

I know the evaporator housings are the same from 77 to 87. I don't know if anything older than 77 is the same or not.

Re: a/c ?'s
 

1977 or so is when GM moved from TXV to Orifice valve.