AC Controls question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jtminton · 06-09-2005, 11:10 AM

I just got a new set of AC Controls (thanks pjmoreland!) for my 72 C-20 and had a question about the vacuum port thing on the top of the assembly. Here is a picture of the new one I just got (picture stolen from pjmoreland's thread):

Here is a picture of the one I took out of my truck (ignore the red parts, they were put there when I was looking for a new top lever):

As you can see from the top picture, there are three vacuum hose connections on the new one, as opposed to my assembly, which has two connections. Can anybody tell me why? Should I just take that part off of my old assembly and use it on the new one? Where does that other hose go? I'm pretty sure that the line controls the fresh air vent vacuum pod, but I don't know what the third mystery line is for.

Thanks

chickenwing · 06-09-2005, 11:26 AM

Interesting. I don't have my vacume diagram handy here at work... Will bring it tomarrow and try to help if no one else has.

smokekiki · 06-09-2005, 11:28 AM

here is a thread on the ports...http://67-72chevytrucks.com/vboard/s...threadid=66112

jtminton · 06-09-2005, 11:41 AM

Did they combine the vacuum hoses on 72s?

**pjmoreland** · 06-09-2005, 12:23 PM

Those A/C controls you got from me are out of a 72 GMC.

jtminton · 06-09-2005, 12:24 PM

Quote:

Originally Posted by pjmoreland

Those A/C controls you got from me are out of a 72 GMC.

Hmm. It gets weirder, and weirder.

Hutch · 06-09-2005, 07:56 PM

jtminton
Maybe these will help

badpeanut · 06-09-2005, 11:36 PM

My '72 GMC w/air has two ports. When it started leaking the replacement I got has three; haven't put this in, yet.

**kwmech** · 06-10-2005, 12:43 AM

On my gmc # 1 is the vacuum source. #2 goes to all the vac doors with vac. tees and #3 goes to the heater hose valve.

06-09-2005, 11:10 AM	#1
jtminton II Timothy 4:2 Join Date: Mar 2005 Location: Fort Worth Posts: 361	AC Controls question I just got a new set of AC Controls (thanks pjmoreland!) for my 72 C-20 and had a question about the vacuum port thing on the top of the assembly. Here is a picture of the new one I just got (picture stolen from pjmoreland's thread): Here is a picture of the one I took out of my truck (ignore the red parts, they were put there when I was looking for a new top lever): As you can see from the top picture, there are three vacuum hose connections on the new one, as opposed to my assembly, which has two connections. Can anybody tell me why? Should I just take that part off of my old assembly and use it on the new one? Where does that other hose go? I'm pretty sure that the line controls the fresh air vent vacuum pod, but I don't know what the third mystery line is for. Thanks __________________ 72 C-20 2WD LWB Custom Camper Deluxe 350 4 Speed "Project Lazarus" MY TRUE PRIDE AND JOY "Dangit, Bobby, people will see that oil stain and think I'm a drunk."

06-09-2005, 11:41 AM	#4
jtminton II Timothy 4:2 Join Date: Mar 2005 Location: Fort Worth Posts: 361	Did they combine the vacuum hoses on 72s? __________________ 72 C-20 2WD LWB Custom Camper Deluxe 350 4 Speed "Project Lazarus" MY TRUE PRIDE AND JOY "Dangit, Bobby, people will see that oil stain and think I'm a drunk."

06-09-2005, 07:56 PM	#7
Hutch Registered User Join Date: Oct 2001 Location: Grapevine, Tx. Posts: 2,142	jtminton Maybe these will help Attached Images __________________ John Hutchison Grapevine,Texas 68 1/2 t swb 68 Mustang 69 Jaguar 71 1/2 t swb 88 Supra CompTs6m 93 Escort GT 2005 Corolla XRS

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06-09-2005, 11:26 AM	#2
chickenwing Lovin' Life in Miss.! Join Date: Mar 2004 Location: Puckett, Mississippi Posts: 1,937	Interesting. I don't have my vacume diagram handy here at work... Will bring it tomarrow and try to help if no one else has. __________________ The truck... you hear that? No really, you did hear that?!!!

06-09-2005, 11:28 AM	#3
smokekiki Mike Join Date: Jan 2003 Location: west chester pa Posts: 2,474	here is a thread on the ports...http://67-72chevytrucks.com/vboard/s...threadid=66112 __________________ 70'c/10, 71 suburban4x4 402bb, 72suburban 4/6 drop, 72k/5 4x4 blazer 4" lift 35 tires

06-09-2005, 12:23 PM	#5
pjmoreland Senior Member Join Date: Jan 2005 Location: CA Posts: 5,789	Those A/C controls you got from me are out of a 72 GMC.

06-09-2005, 11:36 PM	#8
badpeanut Not a bad nut after all.. Join Date: Dec 2000 Location: ND Posts: 1,756	My '72 GMC w/air has two ports. When it started leaking the replacement I got has three; haven't put this in, yet.

06-10-2005, 12:43 AM	#9
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,599	On my gmc # 1 is the vacuum source. #2 goes to all the vac doors with vac. tees and #3 goes to the heater hose valve.



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