I posted a thread last year about my AC not working, and I never got around to ever actually getting it fixed…well, I intend to change that this year, and, if possible, I’d like to do it myself it it’s not something crazy hard.
When I turn on my AC, hot air blows. It’s a little warmer than the air that blows if the AC is off, but not much. I first just hooked up a can of refrigerant (the kind with a built in pressure gauge,) and that was a no go. The pressure was high (around 100 PSI.) My friends and I first tried “bleeding” some off, on the off chance whoever had the car before me over-pressurized the system, but still nothing.
The engine DOES rev up when the AC is turned on, and the AC light on the switch also lights up.
Not any difference. It looks like to my untrained eye that the clutch is not engaging…I also did some research and it seems that some 2003 Corolla models had possible faulty AC Clutch relays…so the first thing I’m going to do is buy one of those and replace it…if that doesn’t do it, I assume the whole compressor/clutch system will have to be replaced, and that it wold be best left to professionals?
Before you replace anything you need to see if there is a difference in pressure between the high side of the system and the low side of the system. Usually there are 2 schrader valves, one with a cap with an H on it and one with an L. There should be a 100 psi difference between the high and low side for proper cooling. About 140 psi on the high side and 30 psi on the low side should be good. If there isn’t then there might be a problem with the compressor or you might have a malfunctioning thermostatic expansion valve depending on what your system has. Until you figure out exactly what the problem is you should not change anything.
The fact that you say that the air blows hotter with the A/C on sounds like your thermostatic expansion valve is stuck open and not allowing a pressure difference between the high and low side of the system. This is not a diagnosis, just an educated guess.
If you decide to change any component on your own the only problem I can foresee is that when you replace a compressor you have to bleed out all the refrigerant which is illegal and possibly dangerous if you do not have a vacuum container to store the “used” refrigerant in.
Another thing is that when recharging the system you need to put a certain amount of weight in. Like most pressurized gases/liquids it is measured in weight not volume to compensate for temperature differences. When I recharge A/C systems at work after replacing a component (compressor, condenser, evaporator) the process usually requires me to pull a vacuum on the system for about 15-20 min then to inject a precise weight of refrigerant (R-134) into the system. Usually its between 1.5 to 1.7 lbs for Corollas (if memory serves me).
Of course it is possible to buy the amount necessary and hope you get it right but you may damage your system in the process.
It’s clear from the videos that the compressor clutch is not engaging. While it’s possible the clutch itself is faulty, it is much, MUCH, more likely that it’s not getting the electrical signal it needs. If that’s the case, then any concern about the actual compressor or the operation of other mechanical components of the system is premature. None of that stuff even gets a chance to function when the clutch is not engaged.
There is a low pressure switch that will interrupt power to the clutch if the system pressure is low. Rest pressure (compressor not running) is typically in the 80-100 psi range; pressure below ~25-30 psi will open the switch. If the pressure is that low, it’s because the refrigerant is low due to a leak. Ideally it should be checked with a gauge that’s not hooked up to a refrigerant source (i.e., not connected to an open can that would feed refrigerant into the system). If your gauge was reading the system and not the can, the system is probably full or close to it – or was before refrigerant was bled from it.
If the system is full, it’s time for electrical testing of the series of controls that provide power to the clutch. The relays are among these controls, but there are other components as well. Necessary for meaningful testing are a wiring diagram, an understanding of the system, and a good test light or voltmeter.
Quick update:
It was the relay. I removed the old one, and it was the part number that I had read online had a ‘service bulletin’ regarding it. I got a replacement at the auto parts store, put it in, and the clutch was clearly engaging when the AC was started. It still shot hot air, because of when I discharged a lot of the refrigerant last year, but after a quick boost with some R-134a, it seems to be working. It still takes what I consider a long time to get cold, but better than nothing!
More than anything else I wanted AC so I could get rid of all the damn fog.condensation on my windshield at night. It’s been crazy humid here lately, and without AC, it was a major PITA driving at night.