So when I get the different buttons on the dash for AC controls, no matter what model it is in a little comes out the feet vent and a lot out the defroster. I can control fan speed but that is it. From my research it sounds like it is either a Blend Door Actuator or a problem with vacuum tubes. Is there a way to test these theories without buying and installing new parts?

 

What year is your car?

Does it have Electronic Climate Control?

Jared

 

It's a 1994. And I do believe it does

 

My '88 also has ECC, and although it is a different model control head than yours, they are plagued by the same reliability problems.

Something I would consider is pulling out the control head and bench testing it to make sure it is sending out the right signals to the right places based on what mode has been selected.

I have stumbled across a few YouTube videos that show how to bench test them.

It's not to say that this is your exact problem, just something else to consider.

Jared

 

The blend door has nothing to do with vents or your problem. It controls temperature.

It sounds like you can't control your vents. The most common problem is a defective 3 way check valve. If it cracks or breaks apart then there is not enough vacuum to operate the vent doors.

The check valve is located under the plastic cover on the right side of the engine. It's about in the middle of where the plastic would be. It's a black cylinder with 3 hoses on it. Remove the cover and inspect the valve closely for cracks and any debris around it.

If it is bad you can get it mostly anywhere for under $10.

 

My C68 A/C in my 93 Ruby, just took a dump. After some trouble shooting, I noticed the clutch wasn't engaging so I checked all the A/C related fuses and they are ok. Also, I noticed that the secondary fan did not activate when I turned on the A/C. I got out my voltage meter and there was no current to the clutch. I also noticed that the LEDs on the control panel would flash for a minute or so.

So, I read up in the factory service manual and it states when the LEDs flash there is a fault and to perform a DTC code retrieval which I did and the code was "09" which means low freon. I still have the original R12 and I no.longer live in California and I wonder if I will be required to convert in Arizona. Can anyone tell me if I will be making a mistake in converting the system to R134? I probably won't have a choice in the matter. I just would like to know what to expect if I have to convert the system.

 

I for one will not tell you it is a mistake to switch to R134 as I did it to my 1988 C4 coupe many years ago. Unfortunately to get the system to work it's very best you would need a new condenser as well designed for R134 and even then I doubt it will get as cold as the original R-12 systems did and do everyday. Have somebody hook up a set of R12 gauges and see just how low you are and decide at that time.

Freon R-12 is getting ridiculously expensive even on Ebay. Your original system might be a bit colder if you used the R-12 but at the cost of lots of money. If you only needed one can to make it full again then I would consider it. Especially if you live somewhere like Arizona. There are guys here on this Forum who showed thermometers displaying in the mid-20's of the air returning to the car, every one of them has an R-12 system using the R-12. I personally have never seen anywhere near that cold of air returning to the car, any car that I have owned.

Switching over to R-134 is fairly easy to do with the kit to swap it over. The kits will have new connectors for the hoses and oil and other misc. parts and are well worth the cost. Some even have instructions that explain how to do the swap. I would also replace the drier while the system is open. There are a couple tools you might need, one being a set of gauges for 134 and a vacuum pump to pump down the system before you install the Freon. When I did my C4 it took less than an hour total time of actual work. I drained out the system flushed the lines, installed the drier and then pulled a vacuum and let it sit for a week (4 hours is fine, I had other things to do) then I installed the new oil and then the R134. The C4 gets very cool inside with the R134 and has worked great for me.

Many years ago a local car parts chain was going bankrupt and they had a good sale. I bought three cases of R134 at less than $1 a can. Today the same stuff is closer to $8-10 for a 14 ounce can. The gauges cost $80 and the vacuum pump another $80 and the conversion from R12 to R134 was ~$25. If you can borrow the vacuum pump and gauges the job won't be that expensive. R12 is available but you will pay dearly for it. That is why I would not decide until I knew how much R12 it needs to be operational, anything over 2 cans would lead me towards the R134 route

One more thing to help your AC work it's best. The condenser in my 1988 C4 is aluminum and so it my radiator so I clean the fins on both using "Coil Cleaner" designed for residential AC systems. The coil cleaner I use is a mild acid that removes the corrosion on the surfaces of the aluminum fins down to the bare aluminum which helps transfer heat more effectively. If you are a welder then you might know about Aluminum cleaner they use on aluminum before they attempt to weld it, it does the same thing. All corrosion is removed if you let it sit for a couple minutes and wash it off with a hose (not using a nozzle) so you don't bend any more of the fins. Be careful of painted surfaces as well as it can damage the paint. Every time my home system is serviced they clean the coils thoroughly using coil cleaner to ensure the best heat transfer. Wouldn't that also work on a car as well?

If you go to a shop then they are probably going to tell you that they need to remove the Freon and fill it with some leak detection material and then re-install the Freon from your car. I am not sure if they can put your Freon back in the system or not. A professional will cost you some serious money to do either job. Me, I install some leak stop while filling the system and that was after my system held 28" vacuum for a week. The system does cool the car right down and works great more than 10 years later!

Out in Arizona there must be at least one trustworthy AC technician who can help you out! I wish you the best and hope the R12 Freon is not "That" low!

Good Luck and I hope you can stay cool in your Corvette!

Chris

 

Thank Chris for the well detailed info.

 

I tried to find it and was unsuccessful, I'll look again tommorow. When you say right side what direction are you looking from? Do you mean driver side or passenger side.

 

I believe you problem may be related to the air distribution control unit under the dash. Lots of great information here.

Look to post 27

 

The right side of the engine is the 'passenger" side. Pull off the plastic cover and look about half way down there will be 3 hoses on the valve. It should be very obvious.
This is the first starting point before ripping into the programmer and hoses.