investigator

He's owned a shop for about 30 years, a good trust worthy guy but he's a few hundred miles away in San Antonio and I'm in Houston.

Well, let me ask you this. Should the system still function correctly if I bypassed the condensor fan and the compressor clutch if the compressor is still good and the system is primed to the appropriate oil and refrigerant? If so, could I theoretically rig the system on two toggle switches on fused relays to the key ACC? I mean, I'll have to keep an eye on the temp some how so the evap core doesn't freeze up. I imagine that's the point of the temp gauge. But being that it's so hot, I really only use the A/C when its 85+ anyway. But if this idea makes you cringe, we can move on to the control panel. Is the HVAC panel the silver box that looks an awfully expensive ECU?

investigator

Oh also, the reason why I thought the compressor is bad is because I added 8oz from empty and the reading was 60+ on the low end. When I disengaged the clutch, it shot up passed 130+ but I don't remember the exactly measurements, I just know the pressure was higher than it should have been with only 8oz.

ezone

The comp is likely bad, that's usually why someone would unplug it and stop it from ever operating again. Replace parts as needed. 'If the system was ok, it should have been cooling if you manually ran the compressor and fans.

Toggle switch would not let the compressor cycle to regulate evap core low temperature, you'd soon freeze the evaporator core into a huge ice cube if the AC system did work.




If the comp grenaded or had a meltdown internally, debris (melted teflon and/or lots of gray powder) ends up in the condenser and may plug it up.

Gray powder may have been able to circulate throughout the entire system, and if left in the system may cause the next compressor to fail in short order.

Was there a gray coating inside the pipes when you took apart to replace the expansion valve?

The electronic controls....pull the HVAC dash panel out (same panel you'd take out to replace the radio), find the green 14 pin connector on the back of it and do what I said with terminal A4 (blue wire). The system must have enough pressure to kick the compressor on when you do this (more than 35 PSI).

The blue wire (A4) is the "ac request" line from the HVAC panel, it then goes to the pressure switch, the thermal protector, the MICU and then to the PCM which has final control over compressor clutch and fan relay operations.
LMK if it does or doesn't kick the compressor and fans on when you ground the blue wire.

investigator

I didn't see any coating at all. It was surprising clean and someone had put UV dye in the system. I don't see why. I know where it would be leaking, in the condenser bent into a W shape :')

But other than that, no metallic or powdery substance. So you think the control board with the ***** went into meltdown coincidentally when a separate issue started happening? I'll give it a try tomorrow and let you know.

investigator

I also wanted to add that the A/c button was working a few days ago. All the sudden today it is stuck on. I also noticed the back two windows weren't working but the motors were fine. Could that be another circuit board that went meltdown? Maybe from the heat here in Texas?

ezone

The control panel failing is probably just old electronics, it's a common fail here. Test to be sure though.

It probably went bad AFTER someone unplugged the compressor, if it's actually bad. There's plenty of other things that can stop the system from operating besides the panel.

investigator

A/C button light is working and will turn on and off. However, it is not engaging clutch or fan. I tried A4 and had some trouble finding it but I think I got it and it's a no go. Nothing happens at all. I made a quick video so you can see what happens when the clutch is manually engaged. The low side started feeling a little bit cool but nothing like it should the air from the vents is still ambient temp. Sometimes the needle will jump around a range of about 5-10 PSI and I hear what sounds like a pressure release on the compressor. But then it stabilizes into what you see in the video.


https://www.youtube.com/watch?v=0vJ5...ature=youtu.be

ezone

35 PSI running doesn't look bad, and when the comp is disengaged the pressures will try to equalize. Looked ok so far, and max reading on the gauge looks like about 80?

A high side AC gauge should be able to read about 500 PSI or higher. A system shouldn't be running anywhere near that high though.

Hard to tell much there, and I'm gonna leave fixing the basic AC system up to you.....got that high side pressure gauge yet?



Here's a diagram that looks about right for the car you have. You may need to blow it up to see better....or search google for a better pic



As for the controls that won't turn on the compressor, if you had a scanner that could supply a live data list you might be able to see if the PCM is receiving the AC request signal and see if it then allows the compressor relay to be turned on.

But I'm gonna guess something is amiss in the right side of the diagram here, between the HVAC panel and the PCM.



Ohm test the thermal protector, it should have continuity. So should the pressure switch.

Or you could probe for a ground signal on each item in the circuit on the right side of the page starting at the bottom. If those items above have continuity, ground will be found at each test point.

The HVAC panel supplies a ground to the blue wire in A4 when you turn on the AC buttons, that ground is the "AC request" signal.

Ground should be found on both sides of the pressure switch, and both sides of the thermal protector, and that ground needs to reach the MICU in the dash fusebox.

The MICU then sends the request information in the form of computer data to the PCM which then has control of the clutch and fan relays.

MICUs are another expensive known problem area....Got weird electrical issues? Dome light/keyless/warning beeper/warning lights, or anything else? Will it pass multiplex system self tests?

investigator

Here's the thing, you keep going back to the electrical and the controls that control the clutch. I don't care about the switches right now. Because most likely, someone was messing with this in the past and clogged the system. I'd bet my money that the high side is reading way too high or way too low and there is a clog somewhere preventing flow. 35 PSI is not a good running pressure when it's only at 40% refrigerant capacity. That tells me the system isn't circulating the way it should. Last time I tried to add over 70% the low side wouldn't drop passed 65 PSI with the clutch engaged. Meaning, again, there must be a clog somewhere, or a leaking seal causing the low pressure to push passed the compressor into the high side eliminating it's ability to cool.

Until I get the system cold, I'm not concerned about the electrical. For all I know, the pressure switch is tripped from really high or really low pressure and trying to diagnose electrical problems I don't have until the refrigerant is stabilized is stupid and a waste of time.

You can't tell me that doesn't make sense. I don't have the money for gauges right now so I'll just have to deal until I can.

ezone

Prove it. No guessing.
Also easy to prove. No guessing.
In 10 seconds I could have a positive answer on the status of the switch.
It's there.

Time? TIME?
This thread was started 5 days ago.
In real life I have most of the answers quicker than a cop show catches their criminals on TV.

You still don't have a high side gauge, and you're making wildass guesses about what could be happening inside the system without knowing, even though those guesses are relatively easy to verify as right or wrong.

You already decided it needs a compressor and a condensor.
Put a compressor and condensor in it and see what happens.

investigator

Has it maybe occurred to you there's a reason why I'm 'guessing'? If I had all this money to go spend on meters and gauges, I would have done that rather than searching forums for common problems with arrogant people, such as yourself, with a serious attitude problem.

Again, you're not helping. I'm in a bad situation as it is. I come on here for sincere help from someone who legitimately wants to help and not fuel their ego as you so clearly demonstrated your desire to do so. At this point, I'd rather give a mechanic money I don't have knowing they're a decent human being who could use the money than give you the satisfaction or the ever increasing smug sense of self importance you carry around.


Cheers "Sheriff."

ezone

http://www.autozone.com/landing/page.jsp?name=loan-a-tool

http://www.harborfreight.com/circuit-tester-30779.html

http://www.harborfreight.com/7-function-digital-multimeter-69096.html

investigator

Installed new condenser, evacuated, oiled, and recharged. Now I'm getting cold air but I'm getting heavy engine load and somewhat high readings on the high and low gauges. If I let the clutch out too fast when changing gears, sometime the engine won't keep up with the load of the compressor and it'll stall out. Only happened a few times. It's 83 and pretty high humidity. Gauges are 50 low and between 200-400 high. It will rise to 400 rather quickly and then the fans will kick on and lower it to 200, and it's just a cycle. When I drive, it gets really cold but I'm still concerned at these pressures as well as this leaking sound at the compressor. I'm not losing pressure but it's causing the high gauge needle to jump around in short bursts. I think a seal might be failing internally or the belt might be slipping since it's been squealing. What do you think?

ezone

I have my doubts as to whether or not I should bother typing out any answer at all to you.


200 seems reasonable, but why aren't the fans kicking on at the exact same time as the compressor?

Shall I guess you are still trying to control the AC clutch and fans on your own, bypassing all of the cars built-in controls?

If the PCM has no clue that the AC system is running, it won't have the load compensation factor set up in the idle program.....so it won't boost the idle until after it drops down too far.
If the PCM had the proper input for the AC being on, it may not fall on its face so bad.

BUT pumping 400+ PSI puts a hell of a load on an idling engine and it can cause it to bog down no matter what, even if the PCM had received the 'AC ON' input.

Again: why aren't the fans turning on at the exact same time as the compressor?

How much did the pressure gauge set cost you?

investigator

Nope, fans are working by themselves and aren't jumped. Only thing that is jumped is compressor clutch. Pretty sure the thermal protector is bad. Probably just gonna jump it.

investigator

So, it turns out I was right. I caved and brought it to a mechanic. Turns out the compressor was failing all along. Probably doesn't have much life left so it needs to be replaced.

Thanks for your help, though Sheriff. It was fun learning about all the parts that weren't broken in case they ever do break! I'll hit you up if I'm ever in Colorado. We make a great team.

ezone

Why does the system reach 400 PSI before the fans turn on?


Was it bad? Did it test as open circuit? Did the system run on its own after it was jumped?


Which part(s) of the compressor was deemed bad?


Will you still need to manually jump the relay to make the AC run after the compressor is replaced?

investigator

I expect if I'm paying as much as I am, that they'll fix it correctly. Why it spikes? I haven't the faintest clue. He said it was a seal leak since it was hissing. But it's just about completely failed. It's not pumping at all anymore and there's no more A/C. And unless the shop I brought it to to evac and recharge messed that part up, I have no clue what else it could be.