86 gt ac / hvac

[Caseindaplace]

Hello!

So I am at a stopping point between tinkering and using the search engine. I’ll go chronological order to my stopping point.

I’ve got an ‘86 GT, all stock minus wheels, MAF / Intake & smog delete. I’m trying to get air to blow out of the dashboard vents. In 86 it’s a lever that you move up and down to control the location. Air DOES blow out of the defrost and feet, however once I switch it to VENT or AC - nada.

Did a little searching and vacuum leaks seem to come up but I had no idea where to look.

forum searching brought me to photos of the vacuum tree. Mine is capped off... I’ll supply photos. Further searching brought me to a diagram of the vacuum lines (where they should go) but I have no idea how to read it and apply it to the engine bay.

IF this is the problem, should I get a vacuum line (size?) from the store and run it to where it needs to go and maybe have air blowing from the vents now?

Respectfully,
Casey

[wraithracing]

Welcome to FEP!

You have no line connected to the A/C side of the Vacuum Tree is the first thing.

Defrost is default for the HVAC when no vacuum is present. First thing I would look at/for is the small black vacuum line that comes out of the firewall thru the Evap/Heater Core opening. The line is very small (1/8" or so) and fairly short. That is the supply line to the HVAC unit. That line should connect to the One way Check Valve. The diagram on the right shows the line as into the Evap gasket and into the passenger compartment. The other line off the Check Valve will go into the reservoir ball under the passenger side fender. If that line is off/broken/leaking you don't have vacuum at the HVAC unit.

Obviously neither of those lines actually have vacuum as those two are connected to the Vacuum Tree at the A/C connection again as shown on your diagram. So You can see the line at the Tree is missing. So back track to the Check Valve and then from there into the passenger compartment and into the Reservoir. If the actual line is missing, then you will need to purchase one to connect to the Check Valve and then into the passenger compartment. Good luck!

[Caseindaplace]

Thank you! I will look at it tomorrow after work.

Would you be able to show a picture or describe where / what the
Evan heater core opening is?
one way check valve
hvac unit
and the reservoir?

when it comes to AC stuff I am completely a noob...

[wraithracing]

I can get a better picture maybe this afternoon if I can make it out to the shop. Otherwise this is the best I have right now.



The Evaporator is mounted inside the passenger compartment. The ends of it poke thru the firewall just inside of the passenger side strut tower. The large canister you see in the picture above is the accumulator which connects to the Evap core. If you look closely in the picture you will see a small vacuum line resting on top of the metal lines. I know it's not the best, but again I don't have any up close pictures of that. In the firewall there is a sponge foam/rubber gasket that the lines go thru. There is a small hole that the vacuum line goes thru near one of the tubes. That is the first thing you want to locate.

That hopefully is there and then hopefully connected to a small black plastic fitting with 3 ports. Two on one side a circular section and another port. The line from near the Evap core will go on one of the two fittings, the other fitting should go to the reservoir which you will not be able to see without pulling the passenger front wheel and fender liner. You should be able to see the line going from the check valve to the passenger inner fender and then disappear under the fender. The other side of the check valve should have small black vacuum line that heads towards the driver side of the car. That ends needs to connect to the A/C port on the vacuum tree.

HVAC unit is the term I and others use to refer to the Evap core/Heater core housing inside the car. You can only get to that after removing the dash.

The reservoir is a small black plastic ball that is mounted under the passenger fender that holds "spare" vacuum for the HVAC system that you can only access by removing the wheel and inner fender liner.

I will try and get you better pictures later if I can. Good Luck!

[Caseindaplace]

Man this is great! I appreciate the time you spent on that narrative lol, I can’t wait to apply it hands on. I’m good with bolt ons and definitely not afraid to take things apart and put them back together. I look forward to any other photos if applicable - if not you have definitely helped a ton. I will get underneath the hood tonight and post an update of my findings!

[Caseindaplace]

I also have a subpar photo of the engine bay from the Ad when I bought it. It was just in my photo album, not sure if it helps but here it is. I’ll take better ones tonight

[wraithracing]

I also have a subpar photo of the engine bay from the Ad when I bought it. It was just in my photo album, not sure if it helps but here it is. I’ll take better ones tonight

Well first it appears you have an aftermarket A/C system. That will add a degree of difficultly. The picture I showed was of the factory installed system. The aftermarket systems were offered by Ford and many others, so it is hard to say what you have. I am guessing it is not a Ford system as the compressor looks very different from anything I have seen installed, but I could be wrong.

Unfortunately I am not sure if much of my explanation will pertain to your situation at this point. I would still look for the vacuum lines, but no guarantees that they will be where I stated they might be. It may require more investigation than originally thought. Good Luck!

[Caseindaplace]

Oh man really? Shoot. I have a picture of the AC compressor. Ford HR980? Something they did after as an add on kit?

[KevinK]

The HR980 was factory installed on the 2.3 4 cylinder. It could be a dealer installed kit. With that said, the controls inside would have been replaced or upgraded. Usually the hvac control panel will say Ford on it for a dealer installed Kit. The basics are the same and you may be able to migrate to the factory design. There may be some documentation in the Ford Service Manuals.

[Caseindaplace]

�� I wonder why this system is in my car? Was it a “better” system?

Seeing that I know what is it, I should probably find a 2.3 schematic of how the system should be.

Having said that, do we still concur that the AC line on the HVAC tree needs to have a line and not capped off to ensure flow of air through the dash vents?

[Caseindaplace]

I got some got some photos of what I found. I’ll post them up. Please let me know what you make of them.

[Caseindaplace]

[wraithracing]

Sorry it appears I was mistaken. I always forget about the little 2.3 compressor. Anyway, as stated it probably is a Ford Dealer installed unit. The good side to that is the system should be a quality unit.

I would still believe that you need some source of vacuum to get the air to blow out the correct vents. I may be wrong on that. I have owned a couple of vehicles with Dealer Air, but never worked on them, so I am no expert. If one of the vacuum lines you were checking out there appear to go back into the passenger area thru the firewall, then I would give it a try by hooking it up to the vacuum tree and see how things go. Hopefully someone with more experience can chime in to help you out. Good Luck!

[Caseindaplace]

Yep I will try. The only tube that runs to the firewall is the large vacuum tube that is directly connected to the compressor. Now I must add that the compressor does not kick on allegedly due to low or no refrigerant in it (low pressure / fluid cut off?). It is still fitted with R12 components so I had planned to flush it and retro it to R134.

with that noted, would the dashboard vents still be an option to have air blowing from them from outside air as the feet and defrost do now? The dashboard vents are not reserved for AC air only is my question

[Caseindaplace]

Just another update, I went ahead and opened the dash a little and checked the HVAC controls. I thought maybe the lever wasn’t working. I can hear the lever which is attchaed to a rod - all seems fine. I can hear and feel it opening different avenues for air. When the fan is blowing, on defrost it blows to defrost, drop the lever down to floor it blows to the floor (lightly), drop the lever to vent and it blows to the floor even harder. Then of course drop the lever to AC and it cuts off due to low or no refrigerant.

any thoughts on that?

[KevinK]

It sounds like the dealer installed hvac controls may be manual/cable driven. The factory unit uses a cable for the temp door but the rest is vacuum operated. The factory hvac control uses a sliding block to switch the positions of the vacuum motors. It uses about 4-6 vacuum lines from the hvac panel to the hvac box.

If you have 2 cables, then it’s totally different from the factory.

[Caseindaplace]

Yes it is definitely controlled manually with a lever. Which is contrary to what is USUALLY installed. The avenue of air is supposed or usually controlled via vacuum but I’ve got manual levers.

having said that, do you think that’s why the AC is capped on the tree and perhaps I need to fully dive into the dash to see the actuator open and close?

once I recharge the AC, do you think that will open the avenue for dashboards vents or separate issues?

[ashley roachclip]

It sound like the cable is sliding in its mount , by your description of how the air flow is when you switch from floor and vent .
You have what appears to be vac. Lines to the reservoir , and interior that are not connected .
On a side note , seeing those factory castor /camber plates , under the shock tower , leaves me wondering about many things .

[dynodon64]

You have a dealer installed A/C system. They were put in by a dealer, because it wasn't built at the factory with A/C to start.
Now in the attached picture of your's, do you see that small black plastic tube going over top of that larger 3/4 inch hose? That is the vacuum line to the a/c unit under the dash. That needs to go to a vacuum source.

[Caseindaplace]

You have a dealer installed A/C system. They were put in by a dealer, because it wasn't built at the factory with A/C to start.
Now in the attached picture of your's, do you see that small black plastic tube going over top of that larger 3/4 inch hose? That is the vacuum line to the a/c unit under the dash. That needs to go to a vacuum source.

Are you talking about the one that is labeled M-15 and connects to the blue piece?

Should I run that to the vacuum tree? Or perhaps the small line that runs from the rear underneath of the intake?

[dynodon64]

Don't know what one the M-15 line is. The vacuum line your looking for is a small black one that goes through the firewall where the A/C lines come out. It is the only one that comes out in that place. It gets tied in with the vacuum ball in the right fender and hooks up to the vacuum T by the brake booster. Look at the right side of the label posted earlier in this post.

[Caseindaplace]

Don't know what one the M-15 line is. The vacuum line your looking for is a small black one that goes through the firewall where the A/C lines come out. It is the only one that comes out in that place. It gets tied in with the vacuum ball in the right fender and hooks up to the vacuum T by the brake booster. Look at the right side of the label posted earlier in this post.

I went ahead and made a video of tracing all lines. Figured it would be better than photos. The only line that isn’t hooked up is the “M-15”

would you be able to tell me what you see or don’t see? Something missing?

https://youtu.be/G-WZQoyOYGE

[KevinK]

Unless some one here has a dealer installed ac on their car, they are sending you on a wild goose chase. It’s not the same as a factory ac!!!

If your unit is cable activated as you stated then you don’t need a vacuum line going inside!!

[Caseindaplace]

Unless some one here has a dealer installed ac on their car, they are sending you on a wild goose chase. It’s not the same as a factory ac!!!

If your unit is cable activated as you stated then you don’t need a vacuum line going inside!!

I gotcha. Ive been told many things so I am just covering everything the best way I can. Below is an enhanced photo of the metal cable that attaches to the position lever. With this, how would you recommend checking the parts? Everything is good up front at the dash that I can see. Perhaps the flap or whatever actually directs air? How would I get to that?

I assume recharging the AC and letting that run will not change anything.

[wraithracing]

Agree that IF your control unit is all cable operated, then the vacuum will not be needed. Maybe it's me, but I can only see one cable lever on your control unit. It may just be the angle and/or I am just missing it. The temperature lever should be cable operated to my knowledge, so if your control unit is ALL mechanical there should be two cables going from the control unit to the HVAC box. IS that CORRECT?

If you do have two cables, then you need to verify that the cables are actually functioning as intended and are going thru a full range of motion. That will require at least looking up under the dash at the cable on the HVAC box to see that the cable is moving a door/lever/etc. of some kind. I believe I have one parts car that was Dealer/Aftermarket A/C and I might be able to get decent pictures of the HVAC box without the dash in the way tomorrow if that helps to determine where the cables actually go to.