ac vacuum lines

[Byco]

OK I figured it out. It took taking the entire unit out of thej truck to diagnos how everything works, or in my case didn't work. But it was all full of leaves and dirt so it needed to be cleaned out anyways. Being I found no documented info on how this stuff hooks up I figured I'd let y'all know what I figured out. First off my system is in an 87 k10 and there are 5 lines. Lines are black with colored stripes. Colors are grey, orange, blue, brown and solid black. First off the grey one is the main vacuum supply for the system witch goes through the firewall. I never found where it actually hooked up so I'm just going to tap into a line that has full manifold vacuum to supply the system. The orange line supplies two actuators there is a tee in it behind the glove box on line goes to the actuator located in passenger side kick panel. This is for the door that allows air from inside the cab to recirculate on Max cool setting. The other orange one off the tee goes through a rubber gromet on top of passenger firewall and connects to actuator located under cowl between Hood and windshield. This lets in outside air.

Hi, is it a special actuator/part number? I cant find anything in Autozone.

Thanks

 

[ninety6]

Looks like auto-zone has 15-71438 -- the blend door (temp conrol). i'm not seeing the others at advance or autozone ....

 

[84 Shorty]

I know this is an old thread but I’m not sure what vacuum port to tie into.

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[bucket]

I know this is an old thread but I’m not sure what vacuum port to tie into.

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It appears you have brake vacuum hooked up and pcv hooked up. The small vacuum port at the base of the carb is hooked to something that can't be seen here. Where does it go to? Also, you have what looks to be the HVAC vacuum supply hose coming from the firewall, but goes somewhere out of the pic. It should go to either that little vacuum port with the mystery hose, or to a vacuum port at the rear of the manifold that you may or may not have.

Also, your distrbutor advance is capped off. That should get plumbed to the little vacuum port at the base of the carb (full vacuum) or to the timed port on the side of the carb that is currently plugged off. Just use whichever the engine seems to like better.

 

[84 Shorty]

To the left of tee is vac hose coming through firewall. Right side of tee goes to vacuum canister on the other side of brake booster. The hose by pcv goes to tranny.

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[84 Shorty]

It appears you have brake vacuum hooked up and pcv hooked up. The small vacuum port at the base of the carb is hooked to something that can't be seen here. Where does it go to? Also, you have what looks to be the HVAC vacuum supply hose coming from the firewall, but goes somewhere out of the pic. It should go to either that little vacuum port with the mystery hose, or to a vacuum port at the rear of the manifold that you may or may not have.

Also, your distrbutor advance is capped off. That should get plumbed to the little vacuum port at the base of the carb (full vacuum) or to the timed port on the side of the carb that is currently plugged off. Just use whichever the engine seems to like better.

I’m not sure if I have any open ports for the hvac vac line. That’s why I was asking here where it should go.

 

[bucket]

I’m not sure if I have any open ports for the hvac vac line. That’s why I was asking here where it should go.

Ok, you can't see in the pic where it goes to. But it should go to full manifold vacuum like the trans. You can just tee it into that line if your manifold doesn't have a spot for a vacuum tree behind the carb.

 

[84 Shorty]

Ok, you can't see in the pic where it goes to. But it should go to full manifold vacuum like the trans. You can just tee it into that line if your manifold doesn't have a spot for a vacuum tree behind the carb.

Having multiple tees on one vac line is ok? Thanks for all the help btw.

 

[84 Shorty]

Could someone explain what the distributor advance does? Should I run a line to this port?

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[dougbert]

Could someone explain what the distributor advance does? Should I run a line to this port?

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http://www.superchevy.com/how-to/ad...now-about-vacuum-advance-and-ignition-timing/

 

[Jerminal]

Hopefully someone can help me out.
I’ve got an 86 GM truck with AC. Long story short my vacuum harness for the climate control is shot and unusable. Does anyone know if they sell a replacement oem or aftermarket. Any help would be greatly appreciated.

 

[bucket]

Hopefully someone can help me out.
I’ve got an 86 GM truck with AC. Long story short my vacuum harness for the climate control is shot and unusable. Does anyone know if they sell a replacement oem or aftermarket. Any help would be greatly appreciated.

Used is the only option I know of.

 

[86gmcfayetteville]

Old thread but useful as hell...
1986 GMC Jimmy full size here. Working on getting the AC back up and running, had some work done on it by a "professional" who "guaranteed his work". Yeah. y'all can figure that out for yourselves. I'm planning on working on it this weekend if the weather is nice. I will document and post pics.

AC Delco no longer sells the vacuum control switch that goes into the back of the HVAC control head, it lists as discontinued. I ordered a couple of similar looking ones with the same number of ports. I'm going to try them and see if I can make them work then post how I did it if successful.

Stay tuned.

 

[Mgfan]

My first post, this site has helped me a lot. I know this is an old thread, but I need some help. My 84 suburban has the 6.2l. My vacuum pump is on the rear on the engine. I am not getting consistent vacuum. I was wondering if the Diesel came with a vacuum tank like the gas engines did?

Also, should I had one or electric pump? Or maybe try to fix the inconsistent vacuum?

 

[austinado16]

HUGE thanks to all the contributors to this excellent thread, especially to the guys posting photos. I just opened my glove box tonight and found the mysterious black/orange vacuum hose (I've just learned goes into the upper firewall area and connects to a vac diaphragm that opens and closes the fresh air door) wrapped around the wires going to the glove box light. Wonder how many years that's been like that? So it looks like I get to remove the cowling below the windshield and repair the cut vac line.

UPDATE: Removed the wipers and cowling, removed the vacuum hose from the fresh air flap vacuum diaphragm, spliced it back onto the black/orange vac hose behind the glove box, and then pushed the repaired hose back through the interior firewall. Hooked the hose back onto the vac diaphragm, and now have full HVAC flap function. I made my splice using some of the thin walled yellow "Tygon" fuel line that is used for 2 stroke string trimmers (weed wackers). Worked perfect.