May 22, 200520 yr OK, I did the R134 conversion the other day (then the weather turned cold again, figures). What I did: swapepd out the compressor (old one was siezed due to oil starvation) cleaned it with brake part cleaner, then filled with Ester Oil. flushed out condensor, evaporator and all lines similarly, with brake parts cleaner followed by compressed air to remove any residue. replaced all O rings, and installed new reciever/dryer, then buttoned everything up. I used a hand vacccum pump connected to the hose from an empty can of R134 to pull as much air out as I could. charged with R134 and started the A/C to be sure it was fully filled (took two 12oz cans) I got good cold air from the vents, and the low side line was cold to the touch so I thought I was good to go. First hot day after, I started hearing some relay going whacko in the area of the evaporator (there are two there). and the compressor was cycling on and off rapidly, making for minimum cooling (Low side line cool, but not cold to touch). This morning I bles off what I assumed was left over air trapped in the reciever/dryer, and resealed. the relay only went whacko once today, and the A/C kept the car cool except for that one time (when the relay was going off). I have good pressure to the low side of the system (fully charged), and when the relay is not "going off" the system cools the car just fine. It also seems to be more likely to "go off" when in "Max A/C" instead of regular A/C. My question: which relay would this likely be? the one facing the cabin area, or the one on top of the evaporator with a temp probe in the fins? is there a way to "fool" the system into thinking that all is well, so it leaves the system running (when turned on)? I'm off on a two or three month trip through some pretty hot areas and will need the A/C working for the trip. . .
May 22, 200520 yr I have had the same problem happen on 2 of my Legacys. I can't remember the name of the controller so I took a picture of it. It controls the compressor cycle so the compressor wont freeze up. Its like a temperature control unit with a thermocouple that hooks into the evaporator. I think this is your problem... Here is the picture... good luck.
May 22, 200520 yr I have had the same problem happen on 2 of my Legacys. I can't remember the name of the controller so I took a picture of it. It controls the compressor cycle so the compressor wont freeze up. Its like a temperature control unit with a thermocouple that hooks into the evaporator. I think this is your problem... Yep I had the same issue on my 92. I replaced it and was good to go.
May 22, 200520 yr I have had the same problem happen on 2 of my Legacys. I can't remember the name of the controller so I took a picture of it. It controls the compressor cycle so the compressor wont freeze up. Its like a temperature control unit with a thermocouple that hooks into the evaporator. I think this is your problem... Here is the picture... good luck. Thanks for the picture! I assume this is located in the engine compartment at the back of the evaporator, and that it can be removed/replaced without discharging the AC system? The A/C on my '90 Legacy was experiencing similar problems: there was a clicking sound which came from somewhere behind the central console of the dashboard, which seemed to be the sound of a relay which would cause the A/C compressor to cycle on and off every two minutes or so. About 8 months or so, my A/C died completely (no cool air at all). I was assuming that the system had lost pressure, but is it possible that the failure of this controller is the problem? Thanks, Zack '90 Legacy AWD auto wagon 158,000 miles
May 22, 200520 yr Just remove the glove box. Right behind that you will find the controller. You need to feel around with your hand on top of the fan box. When this controller fails it will make a clicking noise and then totally dies.
May 22, 200520 yr Wait.....so you only used a hand vacuum pump to evacuate the system? If so, that's not going to work. You need to pull a pretty strong vacuum and keep it there for a certain amount of time to boil off any moisture. A hand vacuum pump won't do that. So you may still a little bit of air in the system, and probably moisture.
May 22, 200520 yr Author OK, that is the relay that I was hoping that it was not. . . that is the one that has a probe in the fins of the evaporator, and it looks like I will be replacing that one soon. that fast clicking is exactly what I'm hearing. . . I have a replacement for it but this is also used. Should I get a new one to replace it, or can I trust a used one (is there any way to test it?)
May 24, 200520 yr Author I have had the same problem happen on 2 of my Legacys. I can't remember the name of the controller so I took a picture of it. It controls the compressor cycle so the compressor wont freeze up. Its like a temperature control unit with a thermocouple that hooks into the evaporator. I think this is your problem... Here is the picture... good luck. That was the part that I was hoping it would not be. . . Upedate: that was indeed the bad part. I swapped it out with a unit from a junked car and the A/C now runs "turns your nipples hard" kinda cold. . . I did not install it into the evaporator fins, as I do not wanna take the evaporator apart for a used part. When I get a new one, I will install if properly. For now the replacement is sitting on top of the evaporator case.
May 30, 200520 yr Just remove the glove box. Right behind that you will find the controller. You need to feel around with your hand on top of the fan box. When this controller fails it will make a clicking noise and then totally dies. OK, I finally got around to doing this and found the controller. However, it seems to be firmly attached in some fashion to the plastic housing which surrounds the evaporator. What do I have to do in order to get it loose? Zack
June 1, 200520 yr OK, I finally got around to doing this and found the controller. However, it seems to be firmly attached in some fashion to the plastic housing which surrounds the evaporator. What do I have to do in order to get it loose? Zack Refreshing this thread, in the hope someone will answer my question! It got a bit buried over the Memorial day weekend... Zack 1990 Legacy wagon auto awd 158,000 miles
June 27, 200520 yr I have had the same problem happen on 2 of my Legacys. I can't remember the name of the controller so I took a picture of it. It controls the compressor cycle so the compressor wont freeze up. Its like a temperature control unit with a thermocouple that hooks into the evaporator. I think this is your problem... Here is the picture... good luck. Ok Subieman replaced the $70 "thermometer" as in picture, plugged it in and fired it up, worked fine even though I haven't placed the probe in the evap fins yet. Subaru parts guy says dash must come apart then crack evap case and remove evap to place probe end into the fins correctly. ;;;;;;Yeaaa that's got to be fun. Then about 45-1hr into our return trip from the Dealer's parts dept. cycling again!!!! Is the next step a "pressure switch"? or yard sale item? Thanks again for a great site for us newbies to vent and learn..
July 11, 200520 yr This site is great don't know if I should reply or start a new post? Ok I replaced the thermostat to the tune of $70, under the dash behind the glove box. Little change,, the a/c stays on a little longer sometimes before cycling on for 2 counts then off for 10. The warmer it is 88-95 the worse it gets it may work up to a half hour starting out when it's cooler or it'll start right away!! no rhyme or reason. Once it starts cycling it doesn't come out of it.... What's next!
July 11, 200520 yr That was the part that I was hoping it would not be. . .Upedate: that was indeed the bad part. I swapped it out with a unit from a junked car and the A/C now runs "turns your nipples hard" kinda cold. . . I did not install it into the evaporator fins, as I do not wanna take the evaporator apart for a used part. When I get a new one, I will install if properly. For now the replacement is sitting on top of the evaporator case. Ok I replaced the thermostat to the Dealer's tune of $70, under the dash behind the glove box. Little change,, the a/c stays on a little longer sometimes before cycling on for 2 counts then off for 10. The a/c works great when it is under 85. The warmer it is 88-95 the worse it gets, it may work up to a half hour starting out when it's cooler, or it'll start cycling right away!! no rhyme or reason. Once it starts cycling it doesn't come out of it.... A/C charged up last years end, a quick check shows good high/low pressure.. Is there a pressure regulator maybe? What's next! Muggy hot in TN
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