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Smalltoid
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| Posted: Jul 18 2013 at 3:28pm | IP Logged
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So, I just bought a 2000 Frontier XE 2.4L a few weeks ago that needed a bit of work. The a/c system was shot, so I decided to replace the compressor, the hoses, the o-rings, the filter/drier, the expansion valve, and the thermo control amplifier (basically everything but the condenser and evaporator, which both seemed to be in pretty good shape). I evacuated the system and gave it a full charge with 134a, oil, and dye. All of the components seem to be operating properly, and I see no signs of leakage from anywhere in the system. When I start the system, it blows very cold air for the first few minutes, then after that, just cool air for as long as it remains on. If I turn it off for several minutes and back on, there will be more cold air, but it might not last as long as before when I started the system after the truck had been sitting for hours. The compressor and clutch seem to be running non-stop. The system is maintaining pressure, and I can't figure out why the cold only lasts a few minutes after starting the system. Any ideas?
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frontierguy
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| Posted: Jul 18 2013 at 6:29pm | IP Logged
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there is an intake sensor in the evaporator that may be the
culprit. do a search for this concern.
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'10 Altima SL
Traded 08 Frontier for 16 Frontier SV CC Long box, quite an upgrade. I do miss the 6 speed and Dynomax ex.
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2011 John Deere X720SE
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lakota
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| Posted: Jul 18 2013 at 10:03pm | IP Logged
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..
It could be an intermittent clog up in the expansion valve
or more likely the thermal control amplifier.
Look at the bottom sticky just above your post..
http://www.nissanfrontier.org/forum_posts.asp?TID=2509&PN=1
Good Luck Don S..
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'99 4x4 3.3 Frontier Se KC Auto, 48,000 miles
'76 4x4 401 Wagoneer QT
'04 FWD 1.8 Sentra '08 FWD 2.4 Camry LE
Fort Worth
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Smalltoid
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| Posted: Jul 19 2013 at 11:56am | IP Logged
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Ok, I just discovered something odd, and I'm not sure if it is related to the problem or not. The compressor is always running when the ignition is on, even if the a/c is off and the blower is off, the clutch remains engaged and never stops unless I pull the control fuse. When the a/c is turned off, this is causing the lines to freeze, which is probably why it is very cold when I first turn it on. Though, if the compressor is constantly running and there is a full charge, shouldn't the cold air always be blowing if the a/c is on? I know it's not a pressure issue causing the compressor clutch to stay engaged. I know it's an electrical issue, though replacing the relay and fuses didn't seem to make a difference. I'm surprised I didn't notice this before if this was actually occurring, and it makes me wonder if this was the cause of all of the a/c issues before I purchased the truck. Any ideas what could be preventing the clutch from disengaging, and could this be related to the lack of cold air?
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Smalltoid
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| Posted: Jul 19 2013 at 12:10pm | IP Logged
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According to the wiring diagram, the compressor line runs from the thermal protector before connecting to the relay. I assume the ground on the thermal protector is what controls the compressor. Is it possible that a short to ground could be causing the compressor clutch to remain engaged? And I'm ashamed to ask, but is the thermal protector (as the Haynes manual describes) the same as the thermo control amplifier, or is there some other sensor that I'm not aware of?
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frontierguy
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| Posted: Jul 20 2013 at 8:09pm | IP Logged
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each year seems to call the device something different. I
just looked, it is called a thermo control amp for that
year.
__________________
'10 Altima SL
Traded 08 Frontier for 16 Frontier SV CC Long box, quite an upgrade. I do miss the 6 speed and Dynomax ex.
Nissan Technician 25 + years
2011 John Deere X720SE
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Nissan Frontier Forums : Problems / Technical
Topic: A/C blows cold, then just cool
