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I have the same problem with my '01 LX coupe. Both 20A fuses are good, don't know how to test the relays. I do know the system is completely empty of r134a. I went to AutoZone today and got a pack of 4 high side valves (they didn't have singles and at $2.99 for 4, who cares?) as the existing one seemed pretty toasted, the low side valve looked practically new.

I was reading the instructions on the can of coolant for how to fill an empty system and one of the employees stopped by and asked a few questions and such, had me start the car up and turn on the AC. He was of the opinion that since the compressor did not engage and the cooling fan(s) didn't kick on, that there might be something else wrong and not to waste my money using the bottle of coolant just yet. I seem to recall reading somewhere or someone else telling me that some cars have a sensor in place to detect extreme lack of pressure and cut off power to the system so you don't wear out/burn up the compressor. I have no idea if there is truth to this or not. Hoping someone here can clarify.

 
Rep Power: 518

An empty AC system will not operate, the compressor is "locked out". It's a safety deal to protect the compressor.
Once there is sufficient pressure within the system, compressor operation is again enabled.

HTH

 
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Thank you for confirming this. I'll charge my system up tonight after I get home from work.

Excellent info, I'll be saving that when I get home.

 
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Okay, so I charged up the AC, once it was done it was at ~45psi on the low side and wouldn't take anymore r134a. The air coming out of the vents with AC on max and fan at max was cool at best. It didn't actually chill until I was under way. Is this normal, or might I need to charge it up a bit more? Perhaps there is something else I should be looking at?

 
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What's the ambient temperature there?
Are both radiator fans running with the AC on? (should be)
Inside fan on full blast
Recirculate on

Run the engine at about 1500 RPM.
What's the high side pressure running at?
What's the low side running at?

 
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Was 79F when I did it. The gauge on the bottle had an adjustable range with an arrow to be pointed at ambient. I did so, and the charge ran up to the PSI right about where ambient was, putting it right about center of the range.

Yes to all.

Not sure the nozzle on the recharge bottle will fit the high side valve, might have to stop by Autozone and get one that will. Can pick up that impact driver while i'm at it. Low side was ~45psi, I will check it again today.

Unintentional, but could be seen as hijacking. I will start my own thread since it appears our problems are different now.

Yeah, I'll make my own thread since the issues are now different.

 
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Creating this thread so that I'm no longer hijacking redbug2's thread.

Bringing things up to speed, my AC wasn't working. Turning the AC on resulted in neither the fans nor the compressor coming on. I'd heard or read somewhere that this was a safety feature, and this was confirmed, so I charged the AC up yesterday. However, despite reaching 45psi on the low side, at idle the air from the vents was cool at best. It did not chill until I was moving.

My final reply in that thread was this:

I'll reply here again once I've checked a few things and made a few more measurements.

 
Rep Power: 518

45 on the low side.... probably overcharged the system. HIGH side readings are just as important as low side.


Jeez....Threadjacked by someone else with RED in their handle LOL

 
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Moved some of the posts to this thread....
Let me know if I got any wrong posts that shouldn't be here.
Sorry, I can't rearrange posts due to timestamps.

 
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The can charges like that aren't meant to hook to the high side ever. You need gauges for that. Running it isn't supposed to ever have high side to the can. It can overpressure the can and blow it up. I honestly wish they wouldn't sell those single charge things. Like ezone said high side is just as important as low side. Sounds like maybe yours was, but alot of guys buy those things to "charge" a system that doesn't need it...

 
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As for overcharging, according to the can I got, the pressure was supposed to be safe as long as the needle was between the V of red lines in which the center arrow for ambient was placed.


Yeah, I didn't hook it to the high side at all. Pretty sure it wouldn't have fit anyway, the diameters are different for the valves and such. Mine was completely empty of coolant so it definitely needed a charge, however a coworker brought up a good point, the proper way for this to have been done would have been to vacuum void the system before charging. Still works, but it will work better when done right.

I'm probably going to leave it as is for now and then once I take care of some more important things like getting the front driver side wheel bearing and hub replaced, I'll see about getting the AC done right.

 
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Okay, so I had the guy who did my wheel bearing replacement check the AC system as well. Basically the compressor is shot, and according to him, it would be good to replace the dryer(some part with a desiccant bead filled bag in it?), and likely since the reed valves are gone, he says the AC radiator will probably need to be replaced as well because they're not flushable due to the piping being too small, and there would most likely be metal shavings from the compressor lodged in it. Quoted me $800 - $900 parts & labor for reference. He did say that as far as charging it goes, I was really close to having it just right (not quite enough charge).

I'm curious what others think about the claims about the dryer and radiator, etc. I did note that a few days prior to contacting him I was getting some odd noises when I turned the AC on (managed to last a day without doing that after I charged it up), and now said noises are pretty much constant so I don't run it much. I have other more important things to get done with this car before I worry about a creature comfort like the AC, esp. at that kind of cost.

 
Rep Power: 518

If you can get by without AC at all, just leave it turned off and ignore it LOL. You can get a shorter belt to bypass the compressor too.

IF the compressor shot craps with internal damage, then he's probably right. It would be very likely to have debris strewn throughout the system up to the filter point, which would be the drier. So, compressor/condenser/drier, plus flushing out the lines between each item if possible. Maybe replacement of the flexible discharge hose...

I guess the next step would be to recover the freon out of the system, open it up and check for debris and dark gray powder in the high side pipes. This would be a huge clue that the compressor is grinding itself to death and is sending garbage into the system.. If the gray is found at the compressor discharge pipe, then I'd go to the drier and check for the same condition inside its outlet pipe to see if the gray material has gotten past the filter.



It's not just metal shavings that come out of a grenaded compressor, there's powdered aluminum and melted teflon --- that can migrate with heat and flow. You can't flush that stuff out of the condenser using the methods commonly available to us.