Need Air Conditioner Help
 

Unfortunately, I find myself in a but of a fix. I have a CAV GT40 replica with mostly South African parts. It seems that my Air Conditioning Control Box has gone on the Fritz and I need to replace it. I was wondering if it looked at all familiar to anyone and if it is something you may give me a lead I may pursue to to source a replacement. The U.S.A. CAV rep indicated that the part in question is no longer made and I will need so install a substitute but was unaware of what that might be. I've also contacted the factory and they no longer stock the item.
Voltage goes in into the unit but none is distributed to the A/C pressure switch, compressor or condenser fan. The part number on it is 05-016-004-01 (as seen in the pictures I have attached). I was hoping that if I couldn't find a part, could you possibly advise me of anyone that may know any appropropriate substitutions or possibly direct my inquiry.

Thanks so much,
Veek

That control box appears to be nothing more then a series of relays all bundled together. You could easily replace that box with 3 relays if you want. Not knowing how the system is wired exactly I'll give you an example.

In my mind you only need 2 relays, one for the fan and one for the compressor. The prssure switch has no amp draw and does not need a relay to carry the load. Voltage from the switch is sent to the pressure switch and then from the pressure switch to the control side of the relays. Main battery voltage is sent to one side of the relays and out the other side to the compressor and the fan(1 relay for each).

When you turn the switch to on if the pressure switch is closed like it should be it will send control voltage to the relays for the fan and compressor...closing those relays and bringing on the compressor and fan. When the system cools down and pressure drops and the switch opens it will drop voltage to the control side of the relay and turn the compressor and fan off. you may have a pressure switch for the condensor fan. If that be the case then the control voltage for the fan relay needs to run through that first and that switch will control the fan coming on and shutting off.

Make sense...lol.

Thats pretty much it Z-Link. Myself, I'd wire it so the condensor, evaporator fan AND the compressor run all the time IF the AC is turned on. The Evap fan would run on minimum speed at all times and be subject to increased speed based on a manual switch selection.

I'd wire in the safty switches for high and low pressure to stop the compressor but I'd leave the condensor fan running all the time the AC switch was on.

You will note the "box" does not have that many wires going to it and I suspect this is essentially the primary function it serves. Protection of the compressor more than anything else.

While in theory this is fairly straight forward it will be costly to hire someone to make these mods as it could be very time consuming. Of course, I'd do it myself and it would cost only nickels instead of dollars.

Assuming this system controls temp by utilizing a thermostatic expansion valve there is no need to cycle the compressor or condensor fan. The Evap fan should ALWAYS run at at least minimum speed to lessen the chance of the Evaporator freezing up. If it did freeze up, the low pressure switch would stop the compressor as a safty. The low pressure switch stops the compressor if the system gets to low on "freon" and low pressure results. The high pressure switch would stop the compressor if the condensor fan quit working or for some other reason that resulted in excessive high pressure.

Thats the whole purpose of the pressure switch is to cycle the compressor. The expansion valve merely controls the flow of refrigerant through the evaperator. Keeping the evap fan running all the time will not prevent the evap from freezing up.

I like the cond. fan on a pressure switch simply because sometimes when the weather is right...the cond fan does not need to run to maintain a correct head pressure. Too low head pressure will cause liquid to possibly get back to the compressor and cause premature failure.

Either way is good.

Cycling the compressor and/or the cond fan is a good call. In fact, I'd rig up a switch to cut off the compressor based on throttle position as well. Full throttle equals no compressor!

But, I'd like to keep the whole wiring scenario simple. Thus, I'd rely on the T-Valve to control temp and the pressure switchs for protection. Even if the T-Valve is at minimum flow you sure could freeze up the Evap, especially if it's in the recirculate air flow mode. But, thats typical of most all cars. When I'm in recirculate air mode I never run my evap fan at minimum speed, all though it's easy to forget.

My understanding, by the way, is that the GT-40 A/C systems just barely offer enough cooling anyway. Perhaps in a cool weather condition the car might get "cold". :)

You can't run an air conditioner on a race track! :)

I agree with both Ernie and Zlink on the relays. I just installed an A/C on my coupe and I believe there were just two relays. Nothing fancy like yours. Send Hershel Byrd an email (he once delt with CAV cars). His email address is hobcobra@msn.com

Thanks Clois but it was Roaring Forties GT.:3DSMILE:
Veek, I have installed a few of these and I used this PDF from Vintage Air as a guide.

http://www.vintageair.com/AC%20Basic...%2029%2009.pdf

They will even help you if you buy the switches and what all you may need. This shows a simple approach to how it works and how to hook it up.

I hope it helps you out . If can help you just shoot me an email.

Hersh:)

Thanks
 

First, let me thank eah of you. I've posted my dilemma on several sites and this is the first one that actually offered some concrete assistance.
The box takes the input from the temp probes in the evaporator as well as the input from the thermostat temp setting and uses the data to cycle on and off the compressor and condenser fan. I've bybassed the controller as suggested and it simply runs the compressor all the time it's on. As noted, the
A/C on these cars is "balmy" at best and cooling is nothing to write home about. But it is better than nothing. Given that, I'm not too concerned about coils freezing, especially here in Florida.
Hersh, I'm spending some time with the Vintage Air book and it seems to me I can build someting to replicate the process as you all have suggested.
The system already has high and low pressure compressor cutoffs so that isn't a concern at the moment.
I've attached a photo of the controller's internals. I've got them with a computer repair guy who is going to try to bench test the components to see if one is out.

Veek, that looks like a real simple board. There are only a couple of components and they are all through-hole. How are you with a soldering iron?

Any part numbers/manufacturer markings on the PCB?

This is not the first time I've heard that A/C in a GT40 suck or ain't quite up to par. As far as mine is concerned it does great. Mine get so cold that when my wife is riding with me she complains that it is too cold. That even happened a lot back in Arizona. I have never had an issue with the A/C temp in my GT. I have looked at many other GT's and I seem to think it is because they have poor cockpit sealing around the doors or no insulation. I will say that my GT is well insulated and my doors seal very well. I even drilled holes in the spyder and filled it with foam. Another thing my A/C has is a fresh air vent that runs direct to the inside unit. That is something most GT replicas don't have.
So plug up those air leaks and I bet it will help heaps.:3DSMILE:

Hersh:)

Ya just a few diodes and resistor and transistor. One relay on the left but the biggest issue could be the ic chip on the right. If that is gone and they don't support the part anymore then there is an issue.

Let us know how you make out.

Thanks all.

I have the unit at an old television repair shop and he's going to try some bench testing on it. We'll see what happens. I'm also looking at Hersh's suggesting the use of a Vintage Air temp control and adapting that. I'd really like to find something that I can service down the road.

GT40 A/C control box
 

Well, I'm a little farther along. Bench tests indicate the Air Con control unit has a bad internal relay. (It's the black square in the photo I attached below). The good news is that it appears to be a common item part number HG4230-005-Z1C. The bad news is that I cannot seem to find anyone that will sell me less than 50 of them. Does anyone know of a retail electronic outlet that does single items?

Try radio shack or Newark electronics.

Try this link... https://www.pacificgeek.com/productd...asp?ID=2472799

here is the data sheet from the mfr:

http://www.tyhhk.com/pdf/HG/HG4230.pdf

Isn't the part HG4230-012-Z1C?

I did some quick looking and I think this data sheet has a direct cross:

http://74.52.232.215/PPDF/833H.PDF

for 0.65 each at mouser or future and you can buy one.

Here is the mfrs website:

http://www.songchuanusa.com it is the 833H series Form 1C. Looks like they are referred to as Sugar cube relays for automotive use. Go to that page and you can look for a distributor by you. Worth a shot.

Thanks so much, I've got several e-mails and calls out to source it. I'll let you know what happens.

You guys are great!

Problem Solved!
 

With your help I was able to source the relay (From Newark) soldered it in and it's now functioning as new.
Thanks to all!