Guest 97svx Posted July 17, 2003 Share Posted July 17, 2003 My 93 Legacy wagon A/C seems to be rapidly cycling on and off, and there is a clicking sound coming from under the dash. The Normal setting is cooler than the Max setting. What could be the problem? Thanks in advance. Matt Quote Link to comment Share on other sites More sharing options...
Guest Legacy777 Posted July 17, 2003 Share Posted July 17, 2003 Sounds like a pressure issue, either the pressure switch is going bad, or possibly there's too little or too much pressure being generated. First step would be to have the system's pressure checked. Quote Link to comment Share on other sites More sharing options...
Guest 97svx Posted July 28, 2003 Share Posted July 28, 2003 Josh, I had the system topped off with R-12 but it did not take much of it. The compressor is cycling on and off. It seems to be cycling off at 35 lbs. Where is the pressure switch and how is it replaced? Thanks in advance. Matt Quote Link to comment Share on other sites More sharing options...
Guest dashton Posted July 28, 2003 Share Posted July 28, 2003 I had the same problem on my '90 legacy wagon a while ago. It was a little sensor that sits right behind the glove box on top of the condensor(?). The box is about 1" sqare and 3" long. I cut the leads to the box, took it apart and all the solder connections on the I/C board were cracked. I ended up finding another one in a junkyard and spliced it in. If you want to replace the entire sensor you have to purge the A/C system, and pull the whole unit from under the dash. I found it easier just to cut the wires and splice in just the box. It fixed it perfectly. However, I agree with Josh - you should have the system pressure checked first. If that checks out, then try and find the sensor. Good luck Quote Link to comment Share on other sites More sharing options...
Guest 97svx Posted July 28, 2003 Share Posted July 28, 2003 Dashton, thanks for the help. I am getting a clicking sound coming from around the glovebox. I do not understand why I would have to purge the system if the culprit is an electronic component? Matt Quote Link to comment Share on other sites More sharing options...
Guest subieman Posted July 28, 2003 Share Posted July 28, 2003 Yes the same thing happened to my Legacy. It's that little black box behind the glove box. Just replace it and all will be good again! You won't have to purge the system. Good Luck. Quote Link to comment Share on other sites More sharing options...
Guest 97svx Posted July 28, 2003 Share Posted July 28, 2003 What is that little black box called? Thanks, matt Quote Link to comment Share on other sites More sharing options...
Guest 97svx Posted July 28, 2003 Share Posted July 28, 2003 I called a dealer and they said it is the Thermostat Control. Matt Quote Link to comment Share on other sites More sharing options...
Guest dashton Posted July 28, 2003 Share Posted July 28, 2003 Here's what I recall from fixing my A/C: The thermostat control is composed of two units - a probe that sits way down inside the big black box (I think it's the condensor or coil or something) behind the glove box, and an I/C board in the little black box. They are connected by two wires coming out the back of the big box. What happens is the probe senses the temperature and the little black box tells the A/C compressor to turn on or off. It does this by switching a relay that's just above the little black box behind the glove compartment. That's the clicking sound you're hearing - the relay turning the compressor on and off. What goes wrong is the connections on the I/C board crack over time and don't keep a constant connection. There are several ways to fix it: remove the entire temperature sensor (both the probe and box) and replace it with a new part. I'm pretty sure the probe mounts in a fitting in the A/C line and you have to purge the system first to get it out, plus you have to take the whole system apart behind the dash. You can also replace just the I/C box by cutting the wires to the probe and splicing in the new box. You could also cut out the I/C box, open it up and re-solder the circuit board. On my first try I cut out the I/C box, took it apart and re-soldered the connections, and then spliced in back in. This worked OK for about a year, and then it went bad again. About three weeks ago I found a legacy in a wrecking yard with the same sensor and I cut it out and put it in mine. Now everything works perfectly again. Here's what I know on the costs: I think a new sensor from subaruparts.com is about $57. Another person had the whole replacement quoted at about $600 from an A/C shop. My junkyard part cost $8. You're welcome to e-mail me if you have any other questions: dashton@wencor.com Good Luck. Dave Quote Link to comment Share on other sites More sharing options...
Guest 97svx Posted July 29, 2003 Share Posted July 29, 2003 Thanks very much for the detailed explanation. I ordered the Thermostat Control from a dealer for $45. I was reluctant to get a junk part which is 10 years old and may fail soon also. I will replace it soon and post my results. Thanks again, Matt Quote Link to comment Share on other sites More sharing options...
mattski Posted August 16, 2003 Share Posted August 16, 2003 I received the Thermo Control unit but cannot find it behind the glove box. I disconnected the wrong thing and spent 2 hrs re-connecting it. Please provide exact location. Thanks, Matt Quote Link to comment Share on other sites More sharing options...
mattski Posted August 20, 2003 Share Posted August 20, 2003 Bump. Does anyone have a Factory Service Manual for this car which shows the location of the Thermo Control unit? I have gotten two different opinions: On top of the box behind the glove box Inside the box. Thanks. Matt Quote Link to comment Share on other sites More sharing options...
theotherskip Posted August 20, 2003 Share Posted August 20, 2003 this is from the 97 legacy fsm. it will hopefully give you some idea of what you are looking for... it is on the air box, and the fsm says that you have to discharge the system and remove the box to get to it?? i haven't done it and haven't really been in that neck of the woods of my car, so i can't give any more help... Quote Link to comment Share on other sites More sharing options...
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