# A/C problem, getting hot outside, please help!



## mattdw (May 16, 2005)

Greetings. First time to post here, although I do read this forum from time to time when I have something I don't know how to fix. Many helpful folks around.

Anyway, I have an automatic 95 Altima and my air conditioner has developed a problem over the last year. It first started happening last summer and has started back up with the hot weather this year. I don't really have the money to drop on a visit to an overpriced AC repair specialist, but summer is close and 100 degree weather with no cold air is rather hellish.

The a/c is fine and blows cold air, but only under certain conditions. If the car hasn't been sitting in the sun, and the outside temp is about 80 degrees or cooler, no problems. Also, if I am driving on the highway, it is fine there as well. But if it is a hot day and I am in stop and go traffic (which is a frequent occurance as anyone who lives in Austin can attest to), the air coming out of the vents becomes very hot. If I turn off the a/c compressor for a few minutes, or get going fast on the highway, it will blow cold air again until I slow down again. During the spring and fall, when it is cooler outside, this doesn't happen at all, even in heavy traffic.

First I checked all of the fuses I could find (main interior box and box by the battery, any more?). I also bought an R-134a recharge kit with an inline gauge from Advance Auto. I checked the lowside line with the engine running and the a/c on full. The gauge first showed there was ~10psi, but it slowly crept up the 45psi. As soon as it hit 45, I heard the compressor click off. Also, both radiator fans, which had been off, both came on. Pressure dropped back to around 10psi, then the fans turned off, compressor clicked back on, and this cycle repeated. A friend told me that both fans should not be either both on or both off cycling like that with the car in park and the engine on.

I don't know much about a/c systems, so any suggestions are welcome. Does the fact that the lowside hits 45psi mean it doesn't need a charge and the prob is somewhere else? I haven't checked relays yet. I would much rather hope this problem is electrical. I'm willing to try anything I can do to fix it and I'm not afraid to get in there and get dirty, as long as I can make do with what tools I have. Thanks guys!


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## Asleep (Jan 19, 2003)

mattdw said:


> Greetings. First time to post here, although I do read this forum from time to time when I have something I don't know how to fix. Many helpful folks around.
> 
> Anyway, I have an automatic 95 Altima and my air conditioner has developed a problem over the last year. It first started happening last summer and has started back up with the hot weather this year. I don't really have the money to drop on a visit to an overpriced AC repair specialist, but summer is close and 100 degree weather with no cold air is rather hellish.
> 
> ...


i beleive our altima has a one-piece low/high switch on the compressor. if this switch is bad, it will think the compressor is "high-siding" and shut it down. same for low-siding. sounds to me like the switch IS indeed bad. you can try replacing the switch and recharging your system. shouldnt take more than maybe 1 can of refrigerant.


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## mattdw (May 16, 2005)

AsleepAltima said:


> i beleive our altima has a one-piece low/high switch on the compressor. if this switch is bad, it will think the compressor is "high-siding" and shut it down. same for low-siding. sounds to me like the switch IS indeed bad. you can try replacing the switch and recharging your system. shouldnt take more than maybe 1 can of refrigerant.


Thanks, I'll have to check that out, but do you have any more information about where it is or what it looks like? I searched around a bit and can't find much information on that switch. Is there another name it would be called? I don't know enough about a/c systems (or cars!) to know what such a switch would look like if I were staring right at it.


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## Asleep (Jan 19, 2003)

mattdw said:


> Thanks, I'll have to check that out, but do you have any more information about where it is or what it looks like? I searched around a bit and can't find much information on that switch. Is there another name it would be called? I don't know enough about a/c systems (or cars!) to know what such a switch would look like if I were staring right at it.


its the part on the compressor itself that looks like a nut with a wire or wires coming out of it. should be on the side of the compressor and not behind the pulley. when you remove it, if the system is not evacuated, you will lose refrigerant and mighty fast too, so make sure you evacuate the system before you remove it. it looks something like this -


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