Stevo

iTrader: (45)

Ive attached a couple of pictures of the vacuum lines i am talking about. I am trying to get my hvac system to work correctly out of all vents right now it only is coming out of defroster and that happened ever sense i got rid of my heater diverter valve. I need to hook up the line back into the intake somehow. It wont be a problem i can get some plastic 4 way vacuum connectors at the store but i have a question about a few things.

In this first picture what is that hard plastic line im holding eventually run to? It just goes into the wiring harness? Is that part of the HVAC or is that part of the cruise control? If its part of the cruise control i can get rid of it cause i dont have that in my car anymore and i could use this port for the second line im holding. Also what is that black shaped ball that is in the middle of the vacuum connections? Is it a valve of a sort or just an odd shaped adapter?

The other port goes to the vacuum ball under the front left fender.

Hopefully you guys can help me clarify this, ive been digging through my service manual and im just not getting enough good diagrams.

Thanks
-Steve

five7kid

iTrader: (14)

That's a check valve.

Sorry I can't provide much more help than that.

91 camaro racer

iTrader: (2)

the second one almost looks like the line that goes from the map sensor to the tb.

Viprklr

iTrader: (5)

First pic is your HVAC vacuum line.
5.7 is right. That's the HVAC/CC check valve.
That last pic is the vacuum line that goes to the heater divert valve.

sofakingdom

iTrader: (1)

Stop for a minute and think how a car is built.

It starts out as a naked body, and rolls down the production line, and workers or machines add parts to it as it moves along, right? As it reaches various points, there may be options, which either are or are not installed; or maybe there's a choice of options at that point, right? Now if YOU were designing this process, and you were constrained by the actual cost of the installation (which would be directly related to the time it took, and the number of operations or steps per option, and so forth, as well as the cost of the physical items themselves), how would you do it? You'd arrange it so that as the car got to the cruise control station, the worker would pick up a cruise control assembly and it would be as unitized as possible; and they'd bolt it in there in as few motions as possible; and hook it up to just the things it needs to go to, right? Same for HVAC, right?

Well that's EXACTLY how they factory does it. The entire HVAC or cruise (or the stereo or the power seats or the power hatch release or any other optional eqpt) thing is already built up as absolutely far as it can be built, into as complete an assembly as possible; and they stick it into the car. In the case of the HVAC, it comes in 2 main pieces: the ENTIRE thing that goes under the hood (compressor, condenser, lines, evap housing) IIRC it's usually even already charged with refrigerant at the component plant; and the part that goes into the interior (control head, ductwork, heater core, wiring, etc.). They do not, for example, lay up under the dash for 2 hours per car as it goes down the line, putting in a million of those awkward screws the way you and I have to do when we change out the heater core. The wiring harness includes the vacuum lines, and the part of that that goes under the hood, they stick through the firewall and pop the rubber grommet into place, and then plug the wires and lines and things into where they go. Same for the cruise: the WHOLE HARNESS is already built up with the vacuum lines included, and they just pop it in and hook the ends up to wherever they need to go.

The HVAC wiring harness is a complete, self-contained assembly, that goes through the firewall near the heater hose lines. Likewise, the cruise harness is a complete, self-contained assembly that goes through the firewall near the gas pedal.

Now think about what those lines under the hood are doing. The HVAC takes 2 vacuum connections: one that supplies vacuum to the whole system, and one that takes vacuum to the heater control valve; right?? Now where will those lines be? The harness that comes through the firewall near the heater hose lines, right? So you found the line that goes to the vacuum accumulator (that funky orb that they buried somewhere), and you have one left over, right? Where does it go?

Same for the cruise: it needs a line that goes to the "kill" valve on the brake pedal (and the one on the clutch if so equipped); a line that goes to the servo (the thing that yanks on the throttle linkage); and a supply line. Right? Do the same thing: process of elimination. Where will you find them?

It's just a car, it's not rocket science. Everything is super simple and logical and easy, if you just stop for a minute and think about it, and use the logic that the MANUFACTURER (the people who made it in the first place) needed to use when they were putting it together. "BE the {manufacturer}, Danny". And, once you figure out how they put it together, it's AHELLUVALOT easier to figure out how to take it apart in the most logical units that it breaks down into.

85Iroc-Z

iTrader: (4)

Where is the hard vacuum line that goes to the heater valve located? I only have one hard vacuum line coming out of my harness, does this go to the valve in the first picture or does it go to the heater valve?

sofakingdom

iTrader: (1)

That includes the vacuum lines.

Not all of these cars have a heater control valve, especially the earlier ones; and therefore not all have 2 vacuum lines.

If you have only one vacuum line, then it's the supply one, and it goes to the check valve and/or accumulator, depending on which model of car you have. They all work exactly the same, just the physical arrangement of parts is different.

85Iroc-Z

iTrader: (4)

Ok thanks for the help, this makes sense since i dont remember the 85's coming with the heater valve. However my motor is out of an 88 and whoever put it in set it up with the heater valve. What should i do about that not being hooked up?

sofakingdom

iTrader: (1)

Take the heater valve out; and run one heater hose straight from the intake to the heater core, and one from either the radiator or the water pump to the other connection on the core.

Stevo

iTrader: (45)

You tell me!? I know it WENT to the heater diverter valve because i pulled it off. You obviously understand how the system works, my car came with 2 hoses, just like the system you described. I have removed the heater diverter valve and i have it left over...do i just not use it and it will be like the earlier cars? Thats what im confused about.

Viprklr

iTrader: (5)

Cap it. Seal it. Plug it.

sofakingdom

iTrader: (1)

Yes you could just leave the heater control valve off, and plug that 2nd line.

Or, you could put the valve back in and hook it up like it was.

It's not a super critical kind of thing. It'll work fine either way. The AC will get a little cooler if you use the valve, that's about the only noticeable difference.

If the car has cruise and you want that to work too, you'll need to T its supply off of one of those lines; probably easiest to T it off of the line to the accumulator.

Stevo

iTrader: (45)

No no, i removed the A/C and also the cruise control. I just want the heat to work out of all the vents again.

Thanks for the help.

sofakingdom

iTrader: (1)

Sorry to hear about that. Looks like that used to be a pretty nice car.

Stevo

iTrader: (45)

Yup its a hack job now...

At least i havent cut one wire yet.