A/C turns off during operation
I encountered a similar problem not long ago, though it was a freon issue and discovered that it was something totally different when the low port reading was 125psi. Confused at the reading, and inexperienced with AC systems I sought secondary opinions, and disovered a solution to my particular issue. The compressor clutch was not engaging due to a faulty relay, thus the system was not cooling--hence the buildup of pressure on the low port line. Truthfully, there could be a number of things causing your AC to act up, here are some of the things to check first & foremost:
1. AC Compressor Control Relay (defined as "M/G CLT" or Magnetic Clutch Relay) may be failing. This can be located in the electrical box to the right of the battery under the hood.
Turn the car on, set the AC to MAX and let it run for a while. While facing the front of the car, look under the hood on the left side of the engine. Straight down in front you will see the AC Compressor. There is a belt spinning a pulley, and a clutch assembly within that pulley which engages the compressor. Use a flashlight to see if the clutch is engaging. If you find that it cycles on and off, then you could possibly be a bit low on freon..
If you've checked the freon and it's within range, then try swapping the "FOG" relay with the "M/G CLT" relay (DO NOT DO THIS WHILE THE VEHICLE IS RUNNING). After the swap, start the vehicle and set the AC on MAX. Inspect the compressor again to see if the clutch is engaged. If your clutch was not engaging on your prior freon psi check, then check it again while the clutch is engaged and the system is cooling--this will give you the proper reading for your freon levels. If this solves your problem, DO NOT leave the FOG relay in place of the M/G CLT relay. Go to an auto parts store and purchase a new relay--OEM costs about $70.00, standard replacements (which I happen to have part numbers for.. AdvanceAuto: #R6034, or #35874. NAPA: #TEM207703, or ECHAR6034. AutoZone: #MT0610. O'Reilly Auto: #35874) run anywhere from $14.00 to $30.00 depending on where you go, and what quality/warranty you desire.
2. AC Compressor -or- comp clutch may be failing. If the air comes on and cools intermittently and the relay is functioning, then it may be a problem with a slipping belt. Check your tensioner on your serpentine, as well as the belt. Make sure there are no cracks in the belt and that it is tight along its route.
If neither the relay nor the belt are the cause of your problem, then you may possibly want to have your system purged, flushed/cleaned, and recharged... this is the more expensive part of maintaining an AC system.
Hope that solves your problem!
Jun 25, 2009 |
2003 Toyota Matrix