r12 to r134a convertion...? Is this even factory...??

[zBusterCB87]

hi all,

1990 Chevrolet Beretta
3.1 L V6

I replaced accumulator and put the proper r12 to r134a oil into it with proper amount...
I found the low side r12 fill port on the accumulator, I attached a retrofit fitting to r134a onto it...

Where is the HIGH side charging port....?
I checked the entire system and I can't find it at all.

NTB could not do an evac & re-charge because both them and I can not find the high side charging port...

Everything is OEM GM parts too...

Can someone please tell me where this port is...?
Is there maybe something I missed...?

Because I asked the dealer and they said the car is too old and they do not have any information on it anymore...

Thank you for your help!

[Barry]

On my 94 its upfront underneath near the condenser. Its a pain to get to.

[zBusterCB87]

That's where the book and the dealer said they were (I finally got a dealer to tell me)...
But, I followed the pipes more than once looking all around and see nothing...

The pipe I followed:
Compressor: not here, looked...
Pipe between compressor and accumulator/dryer: not here, but that's high pressure line, where is it...?
From accumulator/dryer to firewall, solid pipe, nothing attached...
Other firewall pipe to from A/C radiator: nothing...
Front radiator: nothing
Pipe from radiator to compressor: high pressure and low pressure sensors, and a football type thing that looks like a vaporizer/check valve...

I have been over all these pipes and it does not exist, same on my 1988 Chevrolet Beretta, I follow pipes and it does not exist...

[zBusterCB87]

Ok, I just found it, apparently the book failed to state to remove one of the sensors to access the high pressure line to do an evac...rofl

I'm going to remove the one for the fan and leave the high pressure cut out, then I will make the fan come on and stay on for the A/C...

Thanks for the help everyone, I found this today by accident after randomly clicking cuz I was ready to give up.

But now I have new question:
What do you think of this? leaving sensor out, modding for nonstop fan on A/C, and leaving a High pressure port R-134a fitting in place of sensor..?

[Barry]

After some research it looks like a few cars did come with no high side ports.

I don't see any issue with keeping the fan on every time the a/c is on, it shouldn't hurt anything.

But do you really need the high side port? Yeah its great for diagnostics etc, but I believe you can evacuate and recharge through just the low side port.

[Cliff8928]

But now I have new question:
What do you think of this? leaving sensor out, modding for nonstop fan on A/C, and leaving a High pressure port R-134a fitting in place of sensor..?

That's what I did with mine and it has no issues. The newer ones came with a 3-wire sensor to leave the high side port available. For optimal performance you can also change the pressure control valve in the compressor to the R134a version.

[zBusterCB87]

Yah, I was unfortunately stuck adding a high side port because the NTB shop is apparently not able to do an evac and recharge with only a low side port...
Even with their 5,000 machine or so they claim...

I found this out today:

On pipe passenger side in front: (what I believe to have found)
1) Low Pressure switch.
2) High pressure switch.

On compressor: (what I believe to have found)
1) Clutch control.
2) Fan pressure switch.

What I did was I took the High pressure switch (that is what I think it was) off of the pipe on the top passenger side: the connector had two wires:
0.8 BLK/PNK
0.8 BLK/LT GRN

- the PNK one went to the other sensor and the + side of compressor relay switch, the LT GRN one went to ECM which was sensing stuff...
--------------------------------------------------------------------------------------------

NEW QUESTION:
1) Am I safe having the High pressure switch removed and jumper-ed...??
(Jumper-ed because it is closed by default, then opens when pressure exceeds...)

I can always re-connect it after the initial evac and charge procedure, then I can take the adapter fitting off and put the sensor back on.
Regardless if the fitting or sensor is removed, a shrader valve is in place on the pipe so pressure will not be lost.

Sorry for the questions, the shop manual does not seem to properly explain the sensors and wires because what I trace (visually, and with metering) in the car does not match up with the stated diagram in the book...fail

Thank you for the help, I might be back on later, but I will defiantly be back tomorrow to check.

[zBusterCB87]

But now I have new question:
What do you think of this? leaving sensor out, modding for nonstop fan on A/C, and leaving a High pressure port R-134a fitting in place of sensor..?

That's what I did with mine and it has no issues. The newer ones came with a 3-wire sensor to leave the high side port available. For optimal performance you can also change the pressure control valve in the compressor to the R134a version.

I just made my last post without realizing you posted this, I do like to specify that I'm talking about what I think is the High pressure switch (that is what I think it was) off of the pipe on the top passenger side: the connector had two wires:
0.8 BLK/PNK
0.8 BLK/LT GRN

- the PNK one went to the other sensor and the + side of compressor relay switch, the LT GRN one went to ECM which was sensing stuff...

[Cliff8928]

I honestly don't remember which one I removed, it was so long ago. What I do know is that one of those sensors is a high-pressure cut-out and the other is the fan switch. The fan switch is the one that goes to the ECM for sure, I completely removed those wires from the harness when I did the 3400 swap.

Make sure the NTB knows that you use less R134a than R12...

[zBusterCB87]

I honestly don't remember which one I removed, it was so long ago. What I do know is that one of those sensors is a high-pressure cut-out and the other is the fan switch. The fan switch is the one that goes to the ECM for sure, I completely removed those wires from the harness when I did the 3400 swap.

Make sure the NTB knows that you use less R134a than R12...

Yes, of the two sensors on the pipe on top I removed the one that went to the ECM, and the other that had the 12 volts, I left connected!

So, it looks like I did remove the fan switch after all! YAY

Thank you all for the information and help!

PS: I'll be watching them closely, before I did this post and a bit more research and accidentally finding this out, they were looking at my car to try and find the high pressure port, and I was in there showing them and helping them out because they asked, and they broke my car right in front of me....lol
I fixed it, but they kept arguing they are charging me the 40 dollars for the 3 mechanics efforts, even though they broke my car which was a 20-40 dollar replacement part from dealer if they still had it, idk... (I already had a part from the junk yard so it didn't mater).
(If only I could do the A/C evac & charge myself, rofl...lol)


Oh, am i correct in saying this: (?)
1) Low pressure cut off switch is on side of compressor.
2) High pressure and fan switches are on high pressure line on tip passenger side of engine in front.

[ronaconda]

Did you change the orifice tube??? Along with the drier/accumulator, it needs to be changed.

So why do you think the wire goes to the ECM??? When you turn on your a/c (so long as it is pressurized correctly), it signals a request from the compressor to the ECM to run your cooling fan nearly constantly. The reason for the constant run of the fan is for two reasons - obviously to cool the radiator, but to draw the heat from the condenser so your a/c stays cold. You guys cutting up your wiring so your fan stays on all the time when you are running your a/c is something that doesn't need to be done as the design of the system will allow the fan run nearly constantly. If your fan isn't running with your a/c on then something else is wrong.

[Barry]

It sounds like you know what your doing.

http://www.harborfreight.com/air-vacuum ... 96677.html

Get that and a manifold gauge set and do it all yourself. NTB is usually all idiots, I know because I hang out with people there and do my alignments and tires.

[Cliff8928]

Actually, even better is that you can get the manifold gauge set and vacuum pump from AutoZone as loaner tools.

But the Accumulator should be changed as well as the orifice tube as mentioned. The control valve on the compressor is recommended as well.

[zBusterCB87]

ok,

I will look into the loaner tools...

I was at NTB wasted 200 dollars cuz your all right, they are idiots and things just didn't work in my favor.
Mainly the adapter fittings I bought at the auto store from r12 to r134a: their low side pop on connector would not attach and they said I had to buy another 50 dollar conversion kit and come back, they would hold my ticket, and if i didn't come back they were gona charge it as another viset, so I was stuck...

Anyways, the finally figured out their machine was able to charge through the high side port, and I said ok, then i found after the machine finally stuck about 6 ounces of r134a after a vacuum out, then my compressor finally came on and it was not putting enough pressure, it was only 119...
so their machine kept turning off...fail

then I get home and try to charge it up some more with some r134 cans and the compressor refused to start up... So, I manually started it and tried charging and it still blew hot, and I was unable to get and r134a into the system through the adapter, so I'll check into that and then see what happens with full charge...

so I am guessing I might have to change my compressor, but idk yet, I'll see what happens with a full charge, cuz its still low... only 6 ounces...

Also, the orifice tube, that is a different size for r134a, right? or am i changing from fixed to variable?
because idk...
I might just leave it...

do you really think it is necessary to change the orifice tube...?

I'm doing all this over the weekend, I got classes to go to for now...

[zBusterCB87]

Did you change the orifice tube??? Along with the drier/accumulator, it needs to be changed.

So why do you think the wire goes to the ECM??? When you turn on your a/c (so long as it is pressurized correctly), it signals a request from the compressor to the ECM to run your cooling fan nearly constantly. The reason for the constant run of the fan is for two reasons - obviously to cool the radiator, but to draw the heat from the condenser so your a/c stays cold. You guys cutting up your wiring so your fan stays on all the time when you are running your a/c is something that doesn't need to be done as the design of the system will allow the fan run nearly constantly. If your fan isn't running with your a/c on then something else is wrong.

Well I had to remove one of the sensors on the pipe on the front top to add a High Port connector for r-134a...
Well, I cut the connector and forever connected the two sires on it together, one wire went to the ECM, the other went to the idk...
According to the book, but the books diagrams don't match up with the cars wires when i trace them so I'm probably going to put that sensor back and just do it all myself, because I just thought of a way I can do everything through just the low port myself.