saw Posted June 28, 2006 Share Posted June 28, 2006 Been havin trouble with my AC for the past several years. Operates intermittently. The unit is reluctant to come on in the morning or evening - essentially when its cooler. On a hot summer afternoon, it inevitably fires up and may run for 15mins. before shutting off and becoming intermittent again. I've had it to the shop. The first time the guy put a little freon in (~ 1/2 lb - not bad for a 15yr old car) and - maybe its my imagination - it seemed to work better. Improved performance lasted for about a week. Now back to the same Took it back into the shop again, and this time was told its something electric. The intermittency, apparently, is due to the voltage cutting off to the compressor. The guy wanted $180 to troubeshoot + whatever parts would be necessary. When I look into the receiver drier sight glass, the liguid shoots through, stops very briefly, and then shoots through again. I mentioned this inconsistent freon stream to the AC mechanic, but he dismissed it as the cause. This crate isn't worth shoving a lot of money into, so I'm looking for suggestions. When the AC is on, it operates well. The problem is getting it to come on and then stay on. Quote Link to comment Share on other sites More sharing options...
nipper Posted June 28, 2006 Share Posted June 28, 2006 i could have sworn i answered this question before. There is a thermo switch in the ac system. This switch is most likely bad. I dont know if sooby AC systems have circuit breakers that automatically reset, ill look that up. The problem is heat sensative, and that switch operates by monitoring temperitures. I'll answer more fully later. nipper Quote Link to comment Share on other sites More sharing options...
saw Posted June 28, 2006 Author Share Posted June 28, 2006 You did! I sent a follow up email requesting the location of said thermoswitch as well as the AC pressure switches. No answer. i could have sworn i answered this question before. There is a thermo switch in the ac system. This switch is most likely bad. I dont know if sooby AC systems have circuit breakers that automatically reset, ill look that up. The problem is heat sensative, and that switch operates by monitoring temperitures. I'll answer more fully later. nipper Quote Link to comment Share on other sites More sharing options...
nipper Posted June 28, 2006 Share Posted June 28, 2006 You did!I sent a follow up email requesting the location of said thermoswitch as well as the AC pressure switches. No answer. ah ok, you have to forgive me im not feeling well these days. Some muscles and nerves are coming back on line and im miserable. i was supposed to send you a scan? email me at nipper@optonline.net with AC scan in the topic nipper Quote Link to comment Share on other sites More sharing options...
SaltCar Posted June 28, 2006 Share Posted June 28, 2006 Please paste that email here too. Subaru mystery switches need to be here so people, like me, can find them when they search. Quote Link to comment Share on other sites More sharing options...
nipper Posted June 29, 2006 Share Posted June 29, 2006 ill do this tomorrow, i bookmarked. Just on top of everything else i have a fever and want to curl. nipper Quote Link to comment Share on other sites More sharing options...
a97obw Posted June 29, 2006 Share Posted June 29, 2006 I guess it was back about 97 or so that the A/C in my 92 Legacy wagon decided to take a dump. Dealership diagnosed the problem as a bad evaporator, when they removed it from the dash it was very oily and even had a plastic shopping bag stuck to it---only thing we could figure was that the bag was sucked in/fell in from the glove box. That fix cost right at about $1400. Worked well for about a year, then gave up once again. Had a local shop replace every O ring they could. Worked well for almost another year. Last time both the high and low pressure hoses were deemed in need of replacement to the ungodly tune of about $325 EACH just for the hoses. It was then that I decided to "put her down" and bought a 97 Outback with R134:banana:. The 92 wound up getting "donated" to my nephew in Montana....like the A/C is really going to be missed up there! Sometimes you just gotta know when to say when. Quote Link to comment Share on other sites More sharing options...
nipper Posted June 29, 2006 Share Posted June 29, 2006 ok guys i dont know how to load thumbnails here so i emailed them to Saw. Ill email them to anyone who can do the magic and make them work here nipper Quote Link to comment Share on other sites More sharing options...
danbennett2u Posted July 7, 2006 Share Posted July 7, 2006 I could really use the location of that switch as well, I could try posting the pics if you could send them to me Quote Link to comment Share on other sites More sharing options...
91LegLS Posted July 7, 2006 Share Posted July 7, 2006 ah ok, you have to forgive me im not feeling well these days. Some muscles and nerves are coming back on line and im miserable. i was supposed to send you a scan? email me at nipper@optonline.net with AC scan in the topic nipper Where is this heat sensitive switch located? My a/c is working but it seems to be loosing its punch when things get warm. I recently had the a/c system checked and the freon is good and charged correctly. I'm thinking the switch is showing its age and should be changed. Quote Link to comment Share on other sites More sharing options...
nipper Posted July 7, 2006 Share Posted July 7, 2006 it is shown in the Haynes Manual as bing in the evaporator box, with an electrical plug on the side. What do you mean by your ac system checked out fine. What are the pressures. Is the evaporator clear of crud? is the condenscer clear of crud. Are the cooling fans operating, and is the cars temp gauge in the middle. Also there is the expansion valve that can affect cooling also. nipper Quote Link to comment Share on other sites More sharing options...
jjou812 Posted July 8, 2006 Share Posted July 8, 2006 the haynes book says its a thermistor, therefore to bypass it would require a resistor of a certain resistence to simulate whatever temp is needed to keep it running. do you know what resistence that is? or can i just jump it like another poster said? Quote Link to comment Share on other sites More sharing options...
nipper Posted July 8, 2006 Share Posted July 8, 2006 your oout of my realem. Of course there is always the possability of testing it and replacing it, but that may be a little bizzare. The wiring diagram shows three terminals, It interfaces with the the controller, the recirc door, and the main ac switch. test it first, there is no logic in this sircuit so its prbbly an on off switch unless the logic is built into the sensor itself. nipper Quote Link to comment Share on other sites More sharing options...
St Nickolas Posted July 8, 2006 Share Posted July 8, 2006 Where is this heat sensitive switch located? My a/c is working but it seems to be loosing its punch when things get warm. I recently had the a/c system checked and the freon is good and charged correctly. I'm thinking the switch is showing its age and should be changed. When each of mine (2) failed, they would do so intermittently. They'd be ok for a few minutes, then they'd start cycling on and off at the rate of ~1/2 to 4 times per second. The a/c clutch would cycle on and off at this rate which was not only annoying, but I'm sure would wear out the a/c clutch very fast. Notice large amounts of red dust around your a/c compressor clutch? Remove the glove box (2 screws at the bottom of it). The thing has a 3 wire plug connector. Wires on my diagram (Haynes manual 89100) indicate red/black, brown/white, and green/red for 90-94 models in color; brown/yellow, green/white, yellow for 95-98 models.The far end of the thermoswitch is inside the evaporator so you're not likely to want to 'professionally' replace the thing. The switch is to keep the evap from icing. You might get another and insert the biz end of the thing into the evap coils as best you can. I've also had Sooby relays fail when hot, too. There are several of these in the a/c system. What I did, and perhaps what nobody else should do, as I may be toying with my safety: Using a thermometer, my air hasn't ever been that cold (freezing) so I bypassed the thermoswitch. I forget which wires I hooked up to do this. From the diagram, I'm thinking that I hooked the (90-94 models) green/red to the brown/white. Nick Quote Link to comment Share on other sites More sharing options...
91LegLS Posted July 11, 2006 Share Posted July 11, 2006 it is shown in the Haynes Manual as bing in the evaporator box, with an electrical plug on the side. What do you mean by your ac system checked out fine. What are the pressures. Is the evaporator clear of crud? is the condenscer clear of crud. Are the cooling fans operating, and is the cars temp gauge in the middle. Also there is the expansion valve that can affect cooling also. nipper The a/c mechanic I work with (commercial refrigerated trailers) says the expansion valve appears to be clogged. Where it is located? The pressures on the low side are good, the cooling fans are running, the engine temp is at little below halfway on the gauge, the compressor is good and both the condensor and evaporator are clear of crud. Quote Link to comment Share on other sites More sharing options...
nipper Posted July 11, 2006 Share Posted July 11, 2006 The a/c mechanic I work with (commercial refrigerated trailers) says the expansion valve appears to be clogged. Where it is located? The pressures on the low side are good, the cooling fans are running, the engine temp is at little below halfway on the gauge, the compressor is good and both the condensor and evaporator are clear of crud. its located in the HVAC box under the dash beneath the glove box. Luckily the valve is screwed in and not soldered. nipper Quote Link to comment Share on other sites More sharing options...
SaltCar Posted July 15, 2006 Share Posted July 15, 2006 The a/c mechanic I work with (commercial refrigerated trailers) says the expansion valve appears to be clogged. Where it is located? The pressures on the low side are good, the cooling fans are running, the engine temp is at little below halfway on the gauge, the compressor is good and both the condensor and evaporator are clear of crud. The expansion valve (TXV) controls the pressures on the low side. What is it that make him think it is clogged? A clogged TXV would show lower than normal pressures on the low side and possibly higher than normal pressures on the high side. I posted a link to a page on gauge diagnostics here somewhere, you might like it. Quote Link to comment Share on other sites More sharing options...
St Nickolas Posted July 15, 2006 Share Posted July 15, 2006 The expansion valve is inside the system with the freon. You should be real sure of this before you decide to have the expansion valve replaced. Seems to me that if the expansion valve is blocked or partially so, or there is water in the system that ices up and blocks the valve, the high pressure switch would shut the system down. Out there under the hood next to the sight glass should be the pressure switches. One low, one high. Not sure which switch is which: A) Brown/Yellow and brown/red wires. Brown/red should be hot with ignition on. Switch normally closed providing power to air conditioner relay #4 (in fuse/relay panel under hood (closest to driver I believe)). This relay has the other side grounded by none other than the Evaporation Thermoswitch that several have suggested is a likely culprit. Red/Blue wire and black wire. Black wire should always be a ground. Red/blue wire should have power and switch is normally open. What would I do? Test the Evap Thermoswitch first. Remove the 2 screws at the bottom of the glove box. Remove glove box. Find the ET (green/red, brown/white, red/black (3) wires). Jumper the green/red to the brown/white. Try the a/c and see if it works any better. This bypasses the ET, but not any of the pressure switches. Nick Quote Link to comment Share on other sites More sharing options...
saw Posted August 15, 2006 Author Share Posted August 15, 2006 Finally got around to shorting out AC evap. thermoswitch, and, lo and behold, AC now consistently works. Thanks to all who contributed! Picked another switch up at a junk yard and installed. Operates the same as the first! Only works consistently when shorted. Could this switch also be bad, or is there another explanation? Quote Link to comment Share on other sites More sharing options...
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