ptt Posted July 15, 2012 Share Posted July 15, 2012 The system has been converted by PO to R134a. I added about half a can of refridgerant a month ago. Has been blowing high 30s to low 40s until now all of a sudden. Hooked up my gauges and the high side was 165 and low side was pegged all the way to the right on the low side. Something blocked??? Thoughts appreciated...... Link to comment Share on other sites More sharing options...
Ronnie Posted July 15, 2012 Share Posted July 15, 2012 Have you checked to see if the compressor is running? Link to comment Share on other sites More sharing options...
Barney Eaton Posted July 15, 2012 Share Posted July 15, 2012 The low side reading would normally be taken at the accumulator/dryer. Something plugged on the low side would give a high reading.....something like the dryer or filter inside the accumulator dryer. It would be pure speculation ....but a improper changeover to 134 could cause the problem. You must get out as much of the old oil (used with R12) as possible because it is imcompatable with the 134 oil and it will eventually cause problems. Depending on the amount of old oil remaining in the system the results can vary from thickening to almost butter. Link to comment Share on other sites More sharing options...
ptt Posted July 15, 2012 Author Share Posted July 15, 2012 The system seemed to be working fine for last two months, with 38°F showing @ the center dash vent @ 98°F outside ambient temps! The compressor clutch is not engaging. With 165 showing on high side isnt that enough charge in the system to engage the clutch? It was @ 225 psi on the high side last time I had gauges hooked up to it so its lost it somewhere? I have no idea if the conversion was done correctly. It was working fine and just started blowing warm all of a sudden. I have a new accumulator, condenser, compressor and all waiting to convert another Reatta over that has a dead R12 system. Im agreeable with it being something blocking somewhere. Where is the question! Link to comment Share on other sites More sharing options...
Ronnie Posted July 15, 2012 Share Posted July 15, 2012 Try disconnecting the battery cable for a couple of minutes and then reconnect. You might find the AC will start working. If it does connect your gages and see what reading you get. Link to comment Share on other sites More sharing options...
Guest Mc_Reatta Posted July 15, 2012 Share Posted July 15, 2012 165 would be on the high side for a static pressure but since compressor isn't engaging, that's all you have to go on. For a blockage to be a problem, you need the compressor running so no way to verify that until you get it running.Suggest you pull the BCM trouble codes and see if any AC codes are present current or history. Also while in diagnostics mode check the value of BI08 to verify the pressure switch is reporting that there is pressure in the system.If the BCM hasn't locked out the compressor from running, the other places to look are the AC fuse, AC clutch relay, and the clutch itself and the associated wiring and diode. Link to comment Share on other sites More sharing options...
ptt Posted July 15, 2012 Author Share Posted July 15, 2012 I have disconnected battery in the past to get the AC to run again. But not working for me this time. I will check fuses, relays, clutch and such. Where is the AC relay on a 1990? I will post follow-up this evening. Link to comment Share on other sites More sharing options...
Guest Corvanti Posted July 15, 2012 Share Posted July 15, 2012 this may, or not help... i had a similar problem on a "furd" bronco last year. not quite as a "high pressure" as yours and compressor not kicking on. after trying to get a "normal" can of 134-a to be accepted to the system for quite awhile, i found i had a can of 134-a with a push button on top. hooked it up and within 20 seconds, the compressor kicked on and "took" the entire can. i ass-u-med there may have been a clog near the orifice that the extra incoming pressure broke up. i sold the bronco last fall with no problems from the a/c for 4 or 5 months...can't remember the brand name, but it was a tall narrow can compared with the "normal" ac-134 can. was white with blue writing... either got it at a flaps or wally.HTH! Link to comment Share on other sites More sharing options...
Guest Mc_Reatta Posted July 15, 2012 Share Posted July 15, 2012 Fuse is #19 10 amp, relay is relay "J" in the underhood relay center. Link to comment Share on other sites More sharing options...
ptt Posted July 16, 2012 Author Share Posted July 16, 2012 I must be living right....first thing I checked on the 90 Coupe was the #19 fuse and it was blown. AC was blowing 38F on the hwy with 103F ambient temps. I then concentrated on the 90 ragtop.The AC system in the 90 Convertible hasnt worked since got it and I have not even looked into the problem. Hooked up the gauges and high side had 55psi and low side showed zero. I put my vacuum pump on it and vac'd for about and hour. Got it down to 28Hg and it held there for an hour while I went in out of the heat. Disconnected the battery and reset the BCM. Hooked up a can of R134a and it literally slurpped it up fast. It took another 3/4 can of R134a and high side went up to 245 and low side was 38 psi. Road test on I-70 produced same as the Coupe ....38F w/100F ambient. It seems like the Coupe blower motor puts out a stronger volumn at the vents than the convertible but I can live with that. Thanks everyone for your help!!!! Youre all GREAT with your assistance...as usual!!!! Link to comment Share on other sites More sharing options...
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