Hi All, I've had two mechanics attempt to install a VIR Eliminator on my 1976 with factory aircon.
The eliminator is in and I am told it was all gassed up but I am not seeing any cold air. Switching inside the car seems to be working as I can hear components changing as I flick through air conditioner to heater, etc.

The wiring of the compressor and VIR eliminator doesn't look right to me and this is where I think I need your help.

The compressor is connected to cut off switch via the brown and green wires which you can see in the photo below.



The VIR Eliminator is NOT connected with the wiring plug on the side of the VIR Eliminator. The instructions indicate it should be connected to the compressor's green and brown wires but they are connected to the other switch.


Does anyone have one of these setups that could check?
Do I need to jump the green and brown wires from the compressor to both the switch and the VIR Eliminator?

I should add, the reason why I am checking is that my mechanic is now saying that it's probably leaking gas from the evaporator and that I should replace it. My gut says that if this electrical wiring is wrong and all I need to do is loop the VIR Eliminator in it might work.

I appreciate your help!

BTW this is a wider view of the area in case it's needed.

 

PM sent

 

I will draw up a schematic of how to wire this properly this evening. A Sanden compressor only has one wire. The stock compressor has 2, but one is a ground wire.

 

That would be great! I just mock wired it up with no joy.
Brown wire from the existing plug (that was connected to the low pressure switch) was connected to one side of the VIR Eliminator, and then up to the one side of the Low pressure switch. I then did the same for the Green wire but on other side terminals.

 

OK. More information on your system would really help.
You have seen my thread on how to make this work. In this thread I do mention that I had my system changed over to 134 a number of years ago with poor overall results.
Things I need to know, 1. Are you running factory clutch style fan? or electric fans?. 2. which compressor are you running? Factory? or did you correctly install a Sanden?
3. did you upgrade your condenser?
The factory compressor and condenser will never give you satisfactory results in Australian conditions.
Here is the factory wiring.

You may notice I have covered up the late 77 wiring on the right hand side. As the late 77 and up is a more modern system with yet still one more switch.
If you run this system with a low pressure switch only. What happens when your liquid line pressure gets to high?
You blow things up. Thats what. You need a binary switch in place of the low pressure switch if you are running the factory clutch fan. If your running a flex fan god help you.
If your running electric fans you must run a trinary switch.
Answer my questions, and I can walk you through to really cold air.

 

OK. Let's just assume that you have a factory waterpump mounted clutch fan.
Why in bloody hell your even touching the light green wire is beyond me.
With the factory compressor, which is a very poor choice with 134. it will have but 2 wires at the clutch. One goes directly to ground. The other, a light green wire goes to the factory low pressure switch. Weather you have upgraded your compressor or not. this wire should not be touched in any way.
looking at the factory diagram in the above post. you will see from the A.C. control switch a tan. (you refer to it as brown) wire leaves the switch. and on Automatic cars is "T"ed off to some solenoid at the carb. Let's ignore that part as it doesn't matter. (sincerely hope you don't have an automatic). Anyway, doesn't matter.
Starting at where your low pressure switch is. Start unwrapping the wiring harness until you are right across from your new accumulator and cycling switch.


Stock wiring is like this above.

Now you have unwrapped your harness, cut the brown wire and do this.

So. power from A.C. switch out through the firewall. Through the cycling switch, NOT parallel! Through the cycling switch then delete the factory low pressure switch and install a binary switch or trinary switch depending on fan configuration.
Running this set-up with low pressure switch only can lead to disaster! You don't have a Valve in Receiver system anymore!
I know, The instructions don't tell you this. I got ahold of the tech support rep at the "Company in Florida". And nailed him to the cross on this.
Failure to have at least a binary switch can lead to blown lines, blown condenser and possible compressor failure.
I will be posting this up in my VIR thread in the next couple days. I want good photos and the time to do it right.

 

Your first mistake was thinking someone in Australia knows how these American Corvettes work. Every Air-Con guy I talked to here had never heard of Valve in Receiver style air conditioning.
Work on your own car! No one loves it as much as you do.
So NO, They will not know how to wire it properly or what needs to be done to get truly cold air.
I am super poor! You have no idea. I have had my car for many, many years. But if I had to buy it now I would be walking.
I assure you I really did my homework on the least expensive way out. Read my thread. nothing short of what I did will produce truly cold air.
You will NEED a parallel flow condenser. Look at ebay and Amazon for a 16" × 26" universal parallel flow condenser.
You will NEED a modern style Sanden compressor and nessesary mounting brackets.
Yes you have a V.I.R. eliminator kit. assuming with accumulator and cycling switch. If that's all you have you have might get sorta cool air. Cold air will require the above.

 

I took a short video to give you an overview.
Do I know what I’m doing? Nope. :-)
I probably should leave it to the professionals but one of the pros messed up the evaporator hose and now my evaporator likely needs replacement. (I have purchased a new one and it should be here in a week). They also haven’t run the wiring correctly. I figure if I can sort part of it out I can then guide them.
One air con specialist I spoke to wouldn’t take it on!

here is my video overview

 

It's late. I normally don't do the videos at all. if someone posts up a link to YouTube I move on to the next thread.
I can't be bothered with links to another site.
In this case I will endeavour to have a look on the weekend.
And no, Do not leave it up to the "Professionals". if you screw it up, you will learn. if they screw it up you gain nothing. Reread my thread and look at the photos.
I have truly cold air on the tightest budget I could do it on.
Ask questions I am certain I missed something as I did this over 10 months. (I told you I was poor).
In the beginning I too tryed cutting corners because of my budget. Just won't cut it in Queensland.
These cars need good air conditioning or you roast in them.

 

Oh, and I had 3 questions. You didn't answer them.
Please do so I can help.

 

ok, you keep pointing to the low pressure switch next to the sanden compressor on the METAL ac line on the inner fender. that is the LIQUID LINE! high pressure liquefied refrigerant. that is the overpressure cut-off switch. that line is full of refrigerant that has been compressed and then run thru the condenser and it is on it's way to the firewall where it will be released into the evaporator by the orifice tube. dropping the pressure and temperature to cool the interior. the low pressure cycling switch is the one on the accumulator that you are calling the VIR eliminator. the one that is not hooked up at all. do you have gauges? the high side will run from around 130 psi to over 300 psi depending on outside temp. low side will run fron as low as 20 to about 50 or so psi.big pressure change from a 70 to a 100 degree day.

and that flex fan has got to go. if you can't find a correct clutch fan down there, you need to convert to electric fans.

 

another detail. the VIR style did not cycle. so there was no cycling switch. the compressor turned all the time ac was on. the VIR did the shut-orr and turn-on of refrig flow. and the R4 doesn't like to cycle. the A6 is more tolerant of it. sanden is made for it.

 

Yes Derek, That is the liquid line. And No Derek the factory switch does NOT shut off for over high pressure. It is a low pressure switch only designed to cut the compressor if your freon level gets to low. That is why I keep saying that you need to replace that switch with a more modern switch that does have a high pressure shut off. A binary switch if stock mechanical clutch fan. Or a trinity switch if running electric fans.
And I did mention when asking questions about his fan. If you have a flex fan "God help you".
Also with the VIR eliminator system it comes with a cycling switch that needs to adjusted properly that is mounted on top of the accumulator, (another part that is not stock replacing the VIR valve and dryer).
And this is how this started, How to properly wire in the new cycling switch.
And no where in the instructions for the VIR conversion is this detailed out.
And no where in the instructions does it mention that the factory switch in the liquid line is a low pressure switch only.
And any Air-Con expert will tell you. You need a binary switch!

 

From the Factory wiring manual.

From the factory service manual.

The 73 - E77 VIR system did NOT come with a high pressure switch in the liquid line. This MUST be replaced when upgrading the system.
73 - E77 did not have a cycling switch. L77 and up did. they have a thermostatic switch on the evap coil.
But the VIR eliminator kit comes with a pressure adjustable cycling switch. That needs to be wired in correctly.

 

derekderek,
Yes that is a LOW pressure switch.

4-vettes, reasoning why you want the cycling switch wired ahead of the LOW pressure cutoff?
My thinking, IF pressure drops below 32psig do you still want the compressor cycling?
Granted, you will most likely feel the cabin AC temp rise quickly but if you don't what happens to compressor running at LOW pressure?
So does the cycling switch on the OP new system take the place of the thermostatic switch (capillary tube style switch) used on the late 77?
That porpoise of the thermostatic switch is to OPEN Switch Contacts when refrigerant temp falls below 32-33 F. So evap does not freeze up.
When contacts are closed compressor cycles..

 

I see now, the OP new cycling switch is adjustable...got it

 

Yes and they are wired in series, Not parallel. So power has to flow through both switches for compressor clutch to turn on. Really wouldn't matter which one was first in line. And that factory low pressure switch Absolutely Must be changed out. If your condenser can't keep up with the heat. Pressures will build to high and you will blow a line, or the condenser or possibly even blow the compressor.
Not certain what Derek has done about an orifice tube for his home made setup. But sounds like he has yet to get his system up and running.
Mine blows really cold air. I really have done my homework. And I waited until I had everything working as it should before I posted my How To thread.

 

ok, i am sorry that system was designed by idiots. you do not have to worry about that low pressure switch again. as the cycling switch which shuts off when the LOW side drops below 20 to 35 depending on refrig type will have LONG since shut the ac system down before the HIGH side drops to 35 psi. WHO"S BRILLIANT IDEA WAS IT TO PUT THE LOW PSI SWITCH ON THE HIGH PSI SIDE!?!?!? excuse the @#&% out of me for assuming if it was on the high side it was a high pressure switch...

 

Derek, No offence intended in anyway. We are all here to share information and idea's.
In this case it looks like you really didn't study your stock (if you have a 73 - E77) Set-up. You do state in my how to thread that you built your own system using later model parts. Including using a 78 up evaporator. Now the late 77 and up system does use a cycling switch. they have a thermostatic switch on the evaporator. And you are correct that the Valve in Receiver set-up did not use a cycling switch.
Most of us would use the VIR eliminator as replacing the evaporator is a major job. Putting in the eliminator is a minor job.
However, all the modern systems use a binary switch. Located on the high pressure line that is both a low pressure and high pressure switch all in one. Most modern cars also have a computer that knows when you switched on the air so the fan is controlled by said computer.
With our old cars that have been upgraded to electric fans.
It is possible that the engine is not in need of the fans. The switch in the intake manifold or head says engine temp is below the need of the fans. It has no way of knowing that the condenser is indeed in need of fans. Thus the Trinary switch. When high side pressure hits about 220 it sends a ground signal to the fan relay. Turning on the fans for the benefit of the condenser even if engine temp is low.
The VIR system wasn't designed by idiots, the Valve in Receiver system actually worked really well. But, with a mechanically driven fan that was always on and with the type of freon it was designed for.
When changing over to 134 it simply can not be adjusted enough to work properly.
Thus we upgrade the system.
One thing that does not need to be changed is the evaporator.
And one thing that none of the VIR kits don't include or mention is the binary or Trinary switch that must be done.

 

Just to satisfy my curiosity, in the L77 on system is it possible for the high side pressure to get to dangerous levels without the thermostatic switch turning off the compressor?