My A/C stopped working this summer and I'm just now getting around to looking into it. I've done some troubleshooting so here's what I've done already... Checked all fuses and A/C relay, they are fine Jumped A/C Switch at relay and Compressor kicks in (meaning compressor is ok) Checked pressure in system, with the system running pressures are around 32psi which is normal System holds freon so it doesn't seem to be leaking. looked at what i believe to be the low pressure sensor (which would keep the system from turning on if it doesn't detect enough pressure) and its plugged in. I'm not sure how to test the switch to see if it's good. I jumped it and it didn't make a difference... Any suggestions? I'm stuck...
BZZZZZZZZZZZZT. Wrong. Normal system pressure when sitting static (no compressor action) is between 90 and 100 psi. When running the high side needs to be 170~200, low side 15~20. You have a slow leak. The low pressure switch is keeping the system from activating as you do not have enough system pressure for it to operate. You should make an appointment with kingwrex at Classic for him to take a look at it. Servicing the AC system w/out the right equipment and knowledge is no good.
noises dude...noises. And I'm like totally not going to be able to diagnose his leak source over the intArnetz.
LOL well you're not completely right either. I did test with the compressor on. I jumped the compressor at the relay to get it to come on so I could test for low side pressure. I tried both 15ish psi up to 30 psi and neither made the compressor come on without the relay being jumped. I read that the service manual states between 18 and 28psi. I also read that a A/C tech had the best luck getting them coldest around 32 so I tried that as well... The pressure does not change at all. I've let out pressure and charged it back to confirm that pressures were correct. I'm not taking my car anywhere I'll be fixing it myself and I'll buy/borrow whatever tools I need to fix it so please don't try to send me to a shop .
If there were a leak I'd be able to get it to come on atleast for a bit with the correct pressure. Correct?
Until you get your ASE or MACS HVAC certification and have one of these: You don't know what you are doing. /WJM's help. PS: I've worked on more SUBARU AC system than you care to know about. So I fucking know what the god damned pressure are supposed to fucking be.
I'm trying to learn a bit about the specifics of my Subaru's A/C system. I'm familiar with how the system works and how other cars work in particular... What happened to this site? Last time I remember everyone was very helpful... I really don't need a cert to work on my own a/c system... You don't even have any idea who I am... If you know so much why don't you try to steer me in the right direction? If you don't feel like being helpful feel free to leave my thread. Thanks!
I'll all for DIY, but I agree with Will on this one. Unless you can put a vacuum on the A/C system then charge it to the psi he said, you're wasting time.
I did. You are not taking my advice. I was being helpful until you started spouting off information thats incorrect and basically telling me that I'm wrong directly and indirectly telling me that I dont know what I'm doing. The system must be under a vacuum in order to boil all the moisture and other contaminants out, normal atmospheric 'air' is the worst enemy of an efficient AC system. Water will simply destroy the compressor and once the dryer is saturated it will come apart and clog the entire system beyond repair. This process (letting the machine pull a constant vac) generally takes hours if done right. On a sealed system with no leaks and you are only replacing a part, 20 mins of vac time is 'ok' and you will not have issues. Otherwise, during the charge process the system needs to 'suck in' the start of the charge in order to properly fill the system. Your car takes 20oz of R134a and ends up with the charge pressures I indicated in post #2 of this thread.
I'm merely asking for trouble shooting advice and information. I only told you that you were "wrong" because of the way you came off initially. It was clearly stated in my first post that I tested the system pressure with the compressor running. I'm extremely hesitant to take advice from someone that comes off cocky and trys to talk down to anyone... Thanks for the info. This explains a little but I pretty much knew this. I do agree that it will be best for me to get the system vacuumed and filled correctly (which I do plan on doing) but only once I diagnose the problem. I don't want to have to refil the system and waste money. Initially I only let a little but of freon out and then charged it back just to confirm that it was correct. The system has not ever been completely drained. From what I understand, I should still be able to get the system to the correct pressures as you said and have the compressor kick on by itself which is not happening. Am I correct on this? This leads me to believe there is some sort of other problem.
Right now I've got the low side pressures to 25ish with the compressor on. I don't have a way to test high side right now since I just have a refil kit. Would testing the high side give me some kind of indication as to what might be wrong? Correct me if I'm wrong but since with the relay jumped and the low side pressure at around 18-25 the system blows cold, I'd assume the pressure is correct?
Yes. It needs to be in the 90~100 psi range when static and 170~200 with the compressor on, at idle. Need to find out the high side pressure first.
Just about any parts store carries that. Prices very. The one pictured is NOT cheap as its from Matco.
Ok. I'll swing by a buddys shop and have the pressures tested with their gauges Monday. Thanks for the help... I'll report back with what I find.
Just wanted to say congrats on digging in and doing the work yourself. And a big thanks to WJM for helping you out with the information. That to me is what this forum is all about. Helping each other out when we have things we need to learn.
Thanks! And agreed, thanks to WJM. We got off to an iffy start but I think we're headed in the right direction. I've done pretty much everything else myself from shimming diffs to complete motor rebuilds and complete custom wiring so I'm not afraid to dig in and do things myself. I'm at one with the fact that I might break something during the learning process... Its worth the knowledge to me...
I also forgot to mention that I jumped the low pressure switch and compressor still did not come on. The low pressure switch is the one (if facing the front of the car) on the right side of the condenser about half way up the line correct?
Haha, that is the main part..you can't be afraid to break something. If you get that out of your head, then it's not too bad. And, I have found as long as you are careful and follow a shop manual, you won't break tooooo much stuff
Yep! The longer you work on cars it seems the more you begin to expect the twist, turns and bumps in the road. The more you expect them, the less they happen lol. That and you begin to set aside 30-50% extra time and budget for the unexpected. :sx:
Yep, thats the one. Its on the high side line. I dont know what the deal is, but for some reason with the SUBARU pressure switches on the AC systems I can never jump them, even per the diagrams, and get the compressor to turn on. *shrug* Again, need the high side pressure readings. Even with the system low the low side is going to be in the ranges you are getting due to the expansion valve doing its job.
Ah good . Thanks. I just went and read about expansion valves so that makes sense... High side readings coming soon...