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Compressor is a Denso about a year old. When A/C switch is on, compressor is kicking on then off every 2 seconds. The car drags back and forth because of it. When the A/C switch is off, no adverse symptoms or noise at all. A/C blows cold. Can this be fixed?
It could be cycling due to the low pressure cutoff, if the pressure drops enough the compressor kicks off and then the lowside pressure comes back up, and it can kick on again. You can use a gauge or if you do not have one, try jumping the low pressure switch (just as a test).
If that pressure is OK, check the AC relay. In mine I found the contacts to be worn and crooked.
There is also a freeze cutoff that could be a problem as well.
-Joel.
because its after 87, your car should have a low pressure switch and a high pressure switch, they are located near eachother on the hose from the condenser to the receiver dryer.
high pressure switch could be faulty or there might be some sort of recent blockage in the system between the compressor and the evaporator, or the expansion valve is stuck nearly closed.
low pressure switch could be faulty or the system could be low (more likely if the hoses werent replaced).
or the temperature sensor could be shutting it off because it gets too cold, but if it only runs 2 seconds or so before shutting off that's probably not enough time to make the sensor freeze up (unless it was faulty)
The low pressure is good (right between the green high and red warning on the gauge). I'll have to look for those switches. I did pull the relay and it looks very clean and functional.
So what are your pressures? Or at least what is the low side pressure at 1000 and 2000 RPM? What's the outside temp?
Re: the relay, in my case that tab that looks crooked in your pic was crooked and the result was a small contact area that got burned. I straightened the tab for full contact and sanded the contacts square and clean with 800 or 1200 or whatever was handy.
Yeah, the tab was not aligned and I will try that. I don't have a legit pressure gauge, just the one that came with the refrigerant can. Temp outside is about 90. So with that burnt contact you had, did you have my same symptoms with the on-off?
Yeah, the tab was not aligned and I will try that. I don't have a legit pressure gauge, just the one that came with the refrigerant can. Temp outside is about 90. So with that burnt contact you had, did you have my same symptoms with the on-off?
Ok, I sanded the contacts, aligned them and tried it out but that did not do it. Not sure if this matters but it worked for the first quarter mile. So next step is this low pressure switch. There are four wires going to it. How do you jump it?
If the arrow on the gauge is pointing to 90 for the ambient air temp, and the needle is right on the green/red line, it could also be the high limit pressure cut off switch cutting in. Bleed a bit of refrigerant off until the needle is back a bit more in the green arc. If that doesn't do it, then it will be electrical with a faulty high or low pressure switch...most probably..
that's a different type of switch than im used to seeing there.
on top of the receiver dryer is there a green electrical plug hooked to a sensor?
if not then maybe you have a combination high/low pressure switch there.
Tiger, you may have nailed it. I just bled some pressure off, a good bit actually. The needle is within the range of normal for 90 degrees but leaning on the high side. I drove it 10 miles and there was no question a difference. It did not have that consistent 'a/c kick in' drag every 2 seconds. At first, it did not drag at all for a few miles but then some random dragging occurred. In the end, at idle, it kicked in every 6 seconds consistently. To me, that links this problem to a high pressure cut of switch like you said. I will also say the AC does not blow quite as cold as it did but I'm not focused on that at all. SO I may try to bleed some more off but if that doesn't do it, then I will take it to a pro that has all the proper gauges and equipment to set it perfectly.
Guys, I'm very happy to report that I released a lot more pressure and took it back out for test run and everything is perfect! It did not kick off once the whole time i had the AC on. So, ultimately too much pressure was causing the high pressure cut off switch to activate continuously causing the problem. At the beginning of the summer, I did my own recharge and obviously put too much in. I cannot tell you how pleased I am that we found the solution. I want to thank you all for your input, this is why I love this forum! I hope some others are able to benefit from reading this. Thanks again!
i would seek out a professional AC shop. it is best, in the long run, to pull a vacuum for a few hours and fill it per the sticker with a dial-a-charge and the proper oil percentage.
07-17-2015, 09:51 PM
A/C compressor kicks on every few seconds!
