2G A/C system not working

[cswindel]

Alright electrical nerds I need to be graced with you assistance as I am no good with electrical.

Current situation:
- A/C is not blowing cold air although the system has been charged recently without the system actually pulling in r-134 because well it dont work haha
- I dont have any prior knowledge of whether it worked or not before or after my teardown of the car
- As a side note I am running OHM harnesses throughout the engine bay and interior and running ECMLink v3

Current untested areas and possible theories:
- A/C compressor is dead and I have not ran 12v power to it such that I can test if the clutch engages or not
- Seeing if there is a setting in ECMLink that I am missing since the a/c and rad fan both kick on when signal for rad fan to kick on gets pushed out
- Thermo sensor is poop but havent checked and the wiring diagrams confuse me on where it is physically located behind the glove box and there arent really any pictures when i look.
- ACCU is poop but havent checked and not sure which wires in the connector to check but havent dug into that area yet because its a pain to reach

Steps I have taken thus far:
- Checked continuity from ECU pin 22 to A/C compressor relay in fuse box (Good continuity)
- With key in ON position and engine not running, I have voltage going to the a/c fan (connector A-39), Dual pressure switch (A-47), and the A/C compressor (A-95)
- With the engine running I checked for voltage at the same connectors and nothing concerning
- With the engine running and a/c switch active I checked voltage again and still nothing concerning. A/C compressor ground showed grounding too.
- With the engine running, I jumped/bypassed the dual pressure switch and no result came about from that
- As mentioned prior, I noticed that the a/c fan and rad fan kicked on at the same time when the signal for the rad fan got passed through the circuit (I dont know if this is normal or not but hey 2 fans is better than 1).

Just wanting to see what your inputs are with this matter before I start going down unnecessary rabbit holes without much guidance (because I will get lost, sad, and confused and it might all occur simultaneously). I believe I have covered the majority of what I have done and assessed to get this thread rolling at least

 

[pauleyman]

I concur that should be enough to turn on all on its own. If low side goes to zero id say yiu have a blockage. If it was open a l time dryer is fried for sure. I concur with previous posts on dryer and expansion valve. Ac isn't hard but it's tedious.

 

[cswindel]

Just to verify the next steps to take:
- Leave HI and LO side of manifold closed and don't let anymore refrigerant in
- Start car and try to run a/c
- Check manifold gauge
- If a/c compressor doesn't kick on and if 0 psi on LO side replace dryer and expansion valve

Which one is the expansion valve? It's not the dual pressure switch on the a/c dryer right?
Also am I looking for anything specific on the HI gauge?

 

[Vladimir]

Expansion valve and dryer are cheap under $50 for sure.Try rockauto, they have pictures of what they look like.

Your second picture, where both pressures equalized in the morning showed around 110psi on both sides when A/C is off. Leave the manifold attached. Start the vehicle. Make sure all the connectors you took off are connected. Hit the a/c button or ask someone to hit it for you while you looking at the A/C clutch. 110 is enough pressure for the duel press switch to allow the clutch to kick ON. Your pressures will immediately start changing and since we know the system is clogged, ounce the pressure goes down below the safe zone the dual press switch will open circuit and cut power to clutch. Reason why I even suggest that 10 second test is just to verify that your system electrical controls work as they should. It's not necessary to do, but I would try that.

A/C system don't like dirt and contaminates. There is never an easy way to go about it ounce dirt finds it's way inside the system. Any good mechanic will change expansion valve as its the most restricted part off the A/C system and a receiver dryer with it, inspect blow through with a/c system cleaner or just use 91% alcohol with compressed air and clean everything , look for a sign of those blue paper towels. It's kind of a long pain in the A$$ process . You must recover all the r134 prior to doing that. Change all the o-rings from the parts you touched. Put everything back together. Create vacuum. Put the specified amount of r134 in it with a bit of whoever PAG oil the system asks for. And verify that the system pressures work as should. Depending on the temp outside. At 70f low should probably be 30-35, high about 200

 

[cswindel]

A/C didnt kick on unfortunately so im assuming the signal wire still isnt pushing 12v to the compressor. Pressure changed but thats probably just a by-product of the engine heating up the a/c lines

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[Vladimir]

Ambient temp from engine heat cause the pressure to increase. It theoretically

 

[Vladimir]

Sorry. It theoretically should have allowed the clutch ON temporarily. But not guaranteed. Regardless the system has to be cleaned and exp valve and dryer changed. If there is an issue still present after the system is cleaned and sealed vacuumed and refilled. The problem will be narrowed down to controls. And you already know that the clutch is working and compressor pumping. You will have to trace electrical wiring/connections from control head, control unit, press switch, therm switch relay .. there is plenty written on this thread already, it should be a good guide

 

[cswindel]

I might just try the electrical stuff first just to be certain because I can at least verify certain parts without needing to evac the system and order parts. Because when the compressor was on it was pulling r134 in and dropping pressure. I just let the car run a bit after I disconnected the power source from the comprrssor and plugged the harness back in. So with the compressor not running anymore, the engine and ambient temp being pretty hot I think that might be why the LO side maxed out with a high psi reading after I shut the car off, much like it just did.

Understandably even if I test all the electrical stuff, those 2 parts could still keep the system from operating but i could potentially narrow down some troubleshooting with what I can test right now

 

[Vladimir]

Yes. If you don't have a recovery machine double check the electric. If you get the compressor to kick on by itself and low side drops again bellow 0 and goes to vacuum, system will have to be recovered and taken apart. It's hard to explain everything, too much to type. But it's all there in the text

 

[cswindel]

Yes. If you don't have a recovery machine double check the electric. If you get the compressor to kick on by itself and low side drops again bellow 0 and goes to vacuum, system will have to be recovered and taken apart. It's hard to explain everything, too much to type. But it's all there in the text

Yeah all good man that makes sense! I really appreciate all the help thus far. Yeah because when the compressor did kick on when I forced it to and then i took that picture of the gauges the lo side pressure was maxed on the upper psi end so it was definitely pulling r134 when I had it on but that doesn't mean anything with a clog haha but if I can get it to kick on then thats progress!

Is it possible that the a/c button could light up but not actually send a signal? I haven't tested the button yet because it lights up and I want to test harder stuff first.

Also im having a hard time finding people steps on how they diag the ACCU and what pins they actually test. There is something else behind the glovebox but no real picture or description of what connector or location

 

[Vladimir]

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This picture that you showed indicates the the system went to maximum vacuum when you forced the A/C on. You went negative pressure on Low side not maximum pressure. High side had all the pressure. System was not circulating and had an obstruction.

Unless you talking about another pic. I'm gonna see if I can pull a schematic from mitchell or alldata when I have a chance

 

[Vladimir]

Or did it go around all the way clockwise? If all the way clockwise that's max pressure hard to tell from pic

 

[Vladimir]

Now that I zoom in I actually see that it's on the other side of the stopper on that gauge. How much freon did you add?

 

[cswindel]

I did a 11oz can for the initial charge and when I had the car running I probably tucked in less than half of the 12 Oz can

 

[Vladimir]

Let's do step by step. When you forced 12 v to the clutch, did it audibly click and matched the speed of the compressor pulley?

 

[cswindel]

Yeah i heard the click and it was spinning without issue. Didn't hear any noises or anything concerning

 

[cswindel]

And the pressure dropped but was fluctuating between about 60-80 psi range on average as the r134 was being slowly let in

 

[Vladimir]

Ok. Before forcing the clutch what pressure did you have on low and high.?


How long did you force the clutch to be engaged and what was the average pressures for the high and low that you've observed. (Give a little more description, 60-to 80 constant on the low?)

 

[cswindel]

If i remember correctly it was about 115psi on both hi and lo. I ran the clutch forced for about 5 minutes I would say and now that I look at the gauges the lo side was fluctuating more in the 35 to 70 psi range. I dont remember the hi side moving much but I wasnt focused too much on it. I think it hit 150 or 200? Maybe but I was focused on various other things and not so much the hi side at the time

 

[cswindel]

But the fluctuation on the lo side was relatively consistent with the clutch forced and r134 flowing through the manifold

 

[Vladimir]

Is it safe to assume that you've added about 16-18 ounces,? And high side did actually bump up close to 200 from 110?

 

[cswindel]

I would say those are safe assumptions. I could simulate it again its just a pain to hook up

 

[Vladimir]

Ok, if our assumptions are factual. Those reading would indicate that the compressor is trying to build pressure.

We can not assume what the high side should reach, because you did not put enough r134 inside the system. Nor do we know the ambient temperature outside at the time of testing. So the high side going up close to two would indicate that the a/c compressor has compression and the reed valves inside it are not stuck or shut.

The low side however was fluctuating and going to 70 psi at times would mostly signify that your condenser might be clogged or restricted. You would have to look at it later, once we figure out why the clutch is not kicking ON by itself when the button is pressed at that time you would also address the dryer and the expansion valve.


Our main thing right now is to.find out why the clutch is not kicking on the compressor, since you have enough pressure and freon for the system to actually turn clutch ON. I'm gonna try to get diagrams from mitchell or all data when I have a chance.

 

[Vladimir]

Also before I get the diagrams let me know when you forced the A/c to be ON, did you see condensation building build on the lines around the expansion valve?

Did the lines change temperature. One got significantly colder on side hotter?

Did anything the air out of the vents change temp?

 

[9 T GSX]

Few tips to add/check:
I noticed you said you have the OHM harness and I am not sure about the 2G but on my OHM 1G harness they do not wire these for A/C. Would start here for sure
Does the evaporator blower fan come on
Could be just a bad pressure switch
Does sound like a blockage more than likely a TXV, could try to unclog it by using some nitrogen and blowing the clog out. Would have to disconnect the tubes. usually 200-300 psi is a good start
When pulling a vacuum its not so much about time as it is about reaching the correct Micron target using a Micron gauge which 500 Microns is the standard for all A/C systems, as at this state it turns water to vapor and it also ensures any trapped moisture boils off into steam and exits through the vacuum pump

If it was me I would definetly look at the OHM harness First > Do a pressure test with Nitrogen to check for leaks "keeps from wasting money on R134A if you have a leak" > depending on Nitrogen Pass/Fail> would replace parts that failed TXV, Drier, condenser, evaporator, O-rings. or just replace all the parts as the evaporator is under the dash and not fun to remove and replace.

To help with the pressures and temperatures refer to this chart.

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[cswindel]

Also before I get the diagrams let me know when you forced the A/c to be ON, did you see condensation building build on the lines around the expansion valve?

Did the lines change temperature. One got significantly colder on side hotter?

Did anything the air out of the vents change temp?

Didn't check for condensation. The high side lines got pretty darn hot. And yes I did notice the air was actually getting colder in the cabin