AC Compressor comes on for 2 seconds only
#1
06-16-2021, 09:38 PM
AC Compressor comes on for 2 seconds only
I have a 2007 Camry LE V6 w/350,000 miles on it. (Our 1993 Camry went 400,000 miles (may it RIP), and my 2002 Avalon has 445,000 on it -- FANTASTIC cars!)
It sat idle for nearly a year before getting a new transmission. Then it was low on refrigerant in the A/C. I charged it, and in the process, apparently over-charged it, and then bled off a bit too much, leaving it under-charged, Then it sat idle for nearly another year thanks to COVID, and my working from home.
It's still a little under-charged, and I now know better, and have a decent gauge, so I think my ability to sense pressure (at least on the low side), and judiciously add refrigerant is OK.
The problem is what the compressor is doing. When the car is cold, I can start it, turn the A/C on full, and everything is great for about 3 minutes -- pressure on the low side looks to be about 35. Then the compressor kicks off, and it goes high, but comes back down to where it should be in a few seconds after the compressor re-engages. All seems good there.
After the car has been on a few minutes, the compressor clutch engages for about 2 seconds, and then disengages. It takes about 4-5 more seconds for the clutch to visibly stop spinning, and then about 15 seconds later, it engages again for 2 seconds, disengages, slows to a stop, and then re-engages 15 second (or so) later. It just stays in that cycle.
What might cause such short cycles on the compressor? they're so short now that I can't get a good reading on the pressure (nor does it cool well after that). I don't have a flashing light on the A/C dial.
Could it be as simple as the compressor relay? I know where it's located, and my local auto parts house has one in-stock for about $15.
Am I barking up the wrong tree?
Any help would be MOST welcome!!
It sat idle for nearly a year before getting a new transmission. Then it was low on refrigerant in the A/C. I charged it, and in the process, apparently over-charged it, and then bled off a bit too much, leaving it under-charged, Then it sat idle for nearly another year thanks to COVID, and my working from home.
It's still a little under-charged, and I now know better, and have a decent gauge, so I think my ability to sense pressure (at least on the low side), and judiciously add refrigerant is OK.
The problem is what the compressor is doing. When the car is cold, I can start it, turn the A/C on full, and everything is great for about 3 minutes -- pressure on the low side looks to be about 35. Then the compressor kicks off, and it goes high, but comes back down to where it should be in a few seconds after the compressor re-engages. All seems good there.
After the car has been on a few minutes, the compressor clutch engages for about 2 seconds, and then disengages. It takes about 4-5 more seconds for the clutch to visibly stop spinning, and then about 15 seconds later, it engages again for 2 seconds, disengages, slows to a stop, and then re-engages 15 second (or so) later. It just stays in that cycle.
What might cause such short cycles on the compressor? they're so short now that I can't get a good reading on the pressure (nor does it cool well after that). I don't have a flashing light on the A/C dial.
Could it be as simple as the compressor relay? I know where it's located, and my local auto parts house has one in-stock for about $15.
Am I barking up the wrong tree?
Any help would be MOST welcome!!
#2
04-13-2022, 07:42 AM
You need to measure high and low side pressures, the amount of gas in the system might be tripping the [pressure switch]
Consider ambient temperature and target temperature[set] (the closer the two are, the more of this rapid switching will occur)
Things to consider as well
ECU also controls the aircon circuit as well
Check if TXV valve if plugged from contaminated system
Was the drier ever replaced
How did you fill the system and with what, did you use scales?
Was the system ever opened and for how long?
Does your system continuously leaks refrigerant?
Consider ambient temperature and target temperature[set] (the closer the two are, the more of this rapid switching will occur)
Things to consider as well
ECU also controls the aircon circuit as well
Check if TXV valve if plugged from contaminated system
Was the drier ever replaced
How did you fill the system and with what, did you use scales?
Was the system ever opened and for how long?
Does your system continuously leaks refrigerant?
Last edited by Rennox; 04-13-2022 at 07:45 AM.
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