Okay, so I've done search after search trying to figure this out without posting a question and still just cant figure out where to start. All I know is it's 115 outside, I have no A/C, and I have heat coming through my vents, not too much fun riding in my vette to say the least. I want to work on it myself and not pay someone to do it.

First things first, I'd like to get rid of the heat coming through. I've searched for "cabin heat" and read about parts that I'm not sure where they're at, water valves, various flaps and so forth, but cant find pictures or diagrams for where they're at. I may have vaccum problems, but I'm not sure where to check that. The Hayne's manual I have is horrible and a waste of 17 bucks. Can anyone tell me how to fix this?

Is there anywhere that I can get a diagram of things. I'm a visual person and can do a lot better when I can see what I'm working on.

Thanks!!

 

For $20 at most places, the AIM is a great help with seeing how your vette was assembled.

I along with many others I'm sure were in the same boat as you. Mine was a little more sever as my problems were complicated by the fact that A/C was added to my non A/C car.

Heat coming through your vents can be a few different causes. The first and most likley is that your seals have long ago dried out and fell apart meaning the vacuum doors to shut off the heat from the core are leaking. If Bubby has worked on your car, you may find that you have something missing and hot air is coming into the cabin from the engine compartment.

Your A/C can have a variety of causes as well as there are many components that make up the A/C system.

With the AIM you can at least get an idea of where these parts are and start looking at them up close.

Kinda hard to pin point some of these issues without taking a good look.

Whatever you think you find, take your time and make a good decision before you invest in a fix.

I wanted to restore my system to OEM standards and after a few hundered bucks decided it was better in my case to just go aftermarket. I needed too many parts to do mine right.

Your case may be different if you have a fully entact system and you just need to replace vent/duct seals and work on the compressor.

I may sell my brand new Hot Rod Air system and concentrate on a long list of other restoration items then circle back to the Hot Rod Air system in a few months.

But in your shoes, I'd start by gettingthe AIM for my year.

 

Start to attack the problem systematically.

1. Is the electrical portion of the system working properly? Things to check here are:

2. If the compressor is not cycling, you should have the system checked with gauges to see if there is sufficient freon in the system. If there is adequate freon, check to see if there is power at the magnetic clutch on the compressor when you turn the A/C system on. If there is power, and the shop thinks ther is adequate freon in teh syetem, you should look at the compressor, it could be a bad clutch mechanism.

3. If the above all check out, move on to the vent control system. This is a vacuum system, including the hot water valve. Slide the controller to different positions with the fan on and verify that you get air from the appropriate places. I.E. defrost from the top of the dash, heat from the lower dash and A/C from the front and side dash vents. If you only get airflow from the heat vents regardless of your control lever setting, you have a major vacuum leak in the system (It defaults to heat with no vacuum).

4. If the vents are working properly, you should move onto the hot water control valve. This units is a source of quite a few issues on these cars, but it can be made to work. There are two items that you should check to verify this part of the control system:

4a. Checking the control circuit. (I have a 78, so you're parts might be in slightly different locations). The temperature control lever on the console moves a cable which activates a vacuum plunger valve located on the top of the inside heater box assembly. For 78 and newer, you should remove the glove box for a good look at this valve. Once you have located the valve, watch the action as you move the control lever. It should be fully depressed when the lever is on the cold side. If it is not, trace the cable from the heater box towards the control lever. You will find a white nylon coupling on the cable. By rotating this coupling, you can adjust the cable to get the valve closed when the lever is at the cold position. Do the adjustment while you are here. From here, you need to see if the valve is sending a vacuum signal to the water control valve wen it is depressed. Looking at the vacuum valve, you will see two small vacuum hoses on it, a black one (vacuum source), and a white one which leads through a grommet in the firewall and goes to the water shut-off valve. Open the hood and find the white hose.

4b. Testing the water shut-off valve. Follow the white nylon vacuum hose to the water shut-off valve. It will be on the passenger side of the car about midway between the front of the engine and the firewall. Remove the nylon hose and attach a vacuum gauge to it. If you have the lever on cold and the vacuum control valve is working, you should see a good vacuum. The vacuum should fall off as the lever is moved to the hot side. It falls off almost instantly on my car, but yours might be different. If you are getting good signal, your control circuit is fine. Test the shut-off valve by applying a vacuum with the vacuum gauge/hand pump while the A/C is on. If the air starts to blow cold, valve is good. If you can't get a vacuum on the valve with the pump, valve is bad and hot water is continually flowing through the circuit and overpowering the A/C.

If you find that the problem with your system is a vacuum leak which is preventing you from shutting off the hot water/getting the vents right, I have found that a simple (temporary) fix is to remove the vacuum line from the air flaps on the air cleaner and route it to the water shut off valve. This shuts off the hot water at all times except for wide open throttle. I had to run mine like that for a week while waiting for some parts.

Of course, the above does not even delve into the freon/evaporator/compressor/condensor side of things. That's a whole other ball of wax.

I have found that the system works better than people give it credit for, but it is not easy to get it to perform. I have gone completely through my system and replaced all of the seals and foam I could find and that made a HUGE difference.

Good Luck

 

THANK you guys very much for taking the time to help me on this. Very very helpful. I think I have a vacuum problem as the vents do not work at all so I'll try to figure out where that is coming in at.

 

OK, Here goes:
1. fill out your profile so we know what year car you have
2. Get an AIM and a shop manual, GM for your specific year
3. Does the AC work at all? Is all of it there?

Shotgun approach:
Open the hood and look on the passenger side of the firewall, there is a blower motor there, does it work on all speeds? (that can be a whole project there)
Here is a pic of some of the stuff I talk about below.


Remove the fan motor, about 5 or 6 screws kind of a pita to get to. Use a mirror and light to look into the hole in the evap box (thats where the blower motor came out of) There is probably a bunch os leaves, dead animals and crap in there, it has to come out. Remove the evap box, there are annother 6 or so screws that hold it together and on the firewall.
Once its all apart clean everything up. Spray the inside of the evap box with undercoating or lizard skin. This will eliminate the engine compartment heat from coming thru the evap box. Thats one source of cabin heat.
Inspect the heater core while you have everything apart, its only $35 for a new one and now is the time if there is any evidence of leakage.
I used simple green and a pressure washer to clean my evaporator, got it nice and clean so that once its fired up the thermal transfer will be MAX.
Reassemble the evap box with all the stuff inside and get a new drier and Orifice tube if yours was so equiped.
Flush the entire ac line system, pump, evap, condensor and lines.
Changing the stock condensor out for a paralell flow condensor is a good thing to do. It is more effecient especially in a R134 system. You should be able to find one from a dodge van or something in a wrecking yard for $20 or $30
Reassemble the rest of the system and get it pumped down and recharge.
That will get the system operating

Efficiency:
you will need to make sure the coolant shutoff valve in the heater line is there and works, a lot of guys use a manual valve, may be a good option out there in the desert, get a 5/8" ball valve at home depot, works good

You will need to go thru all the ducts behind the dash to make sure all of them are in place and properly connected and sealed. These things came with a thin piece of foam wrapped around the duct inserts that died 15 yrs ago, so they leak now, a lot.
There is an uper dash duct that is supposed to be connected to the lower ac duct system, mine had a 3/4 inch gap in it, aluminum duct tape to fix.
One of the tricky ones is the outside air flapper. It is located on the passenger system, end of the wiper tray, under the rear end of the fender. There is a thin vacuume line going to it to close it, default is open. It allows outside air to come in from the wiper tray and get sucked into the blower inlet, got to make sure it works.

There is a soft seal on the kick panel door on the passenger side, the seal dies, you can find a kit in here somewhere for about $20

ok, this sounds like a lot and it kind of is. But you can spend a little time doing reserach and rounding up parts and then actually get it all done in a weekend or 2

 

my A/C does not work AT ALL, and as a matter of fact, even when I change the speeds from Hi to Low, I have absolutely no air flowing what so ever, so I'm guessing there is a problem with the blower motor. The only air I can get in to the cabin right now is the HOT air that blows through the floor vents.

 

Do you hear the fan motor running when you turn it on? Does your compressor turn?

Hot air from the floor vent is lilely the hot water valve in the open position and the heat is coming from the heater core. You really need to see what all is connected, what is working and what is not.

Does your thunb wheel turn smoothly? Do you hear any vacuum when you change from A/C to heat? Can you hear the flaps/door open and closing?

 

Well, for those of you who helped me, thanks!! I actually think the problem was a lot more simple than I expected. I finally just took the dash out and figured I'd start there and work forward. I pulled all of the ventilation tubes and the glove box out so I had a clear view of what was going on with the vacuum lines. Believe it or not, they were all just fine. The only problem I saw was that someone had routed the lines so that one of the lines that connected to the canister on the drivers side of the console was kinked. I rerouted it so that this did not happen again.

As far as the blower motor goes. When I started to pull the dash apart, it miraculously started working. I'm guessing the plug for the switch wasn't making the connection somehow.

But here's what the real problem was. When I moved the lever between A/C, Vent, Heat, and Def., I could hear a vacuum leak which is what made me decide to pull the console out to see where it was coming from. I checked the rubber bushing where the vacuum hoses connect to the switch and it all looked okay. So I decided to pull the switch. Since it was midnight I just decided to pop it apart and see what was going on. Come to find out on the little rubber diverter on the switch that tells the vacuum where to go, there were small amounts of grease built up in the channels which was giving me a vacuum leak. I cleaned the whole switch and bent prongs on the 6 prong metal clip so that it held the switch tighter together. Once I got that done no more vacuum leak and ALL the vent doors opened and shut just like they were supposed to. In all reality I didn't need to take the whole dash out but it was a good learning experience and now I can just move on to actually getting the A/C up and running since I've got this pretty well fixed. I'm sure there will be some small bugs with it, like the small gap that is still left, but that will get fixed in time.

So there ya have it, the only problem was the gunk buildup on the switch.

I also found out that my system has been converted over to the R-134. Will this pose a problem when I go to have the system checked for leaks?

 

Excellent! There should not be any problems with leak detection due to R134A conversion. Sounds like your getting close