AC Turning off and On - Nissan Frontier

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TWG1572

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I was driving my '08 Nissan Frontier this weekend and noticed that the AC was intermittently turning itself off. It was blowing cold air and suddenly I'd notice that the air was warm again. I'd look down and the "on" light was no longer illuminated on the AC button. Pushing the AC button didn't do anything, but messing with the fan knob seems to reset it and the AC kicks back on again. The fan is blowing the whole time. I'd not noticed any issues with it cooling up to this point, seemed to be doing fine this summer.

I didn't find much on Google, other than people having issues with a blower relay. But my symptoms seem different than they describe. I'm hoping it's not an electrical gremlin somewhere and is something simple like low refrigerant. I'd thought about buying either AC gauges or a can of the refrigerant with the gauge on it and seeing what it told me. I guess my alternative is taking it to a shop, which I might also do.

But before I commit to either, I'm curious if anyone has any thoughts on why it might behave this way? If it's something I can potentially fix, I'd give it a whirl. Thanks!
 
Last edited:
Originally Posted By: Donald
I would say its low on refrigerant. The low pressure limit is cutting off the compressor.
Sounds right to me.
 
Based on that, is it worth giving one of the cans of refrigerant a whirl? Looks like there are some pretty good experiences with them from what I can see online. For $30, the price is right.
 
I don't think it's low on refrigerant. And the reason I don't is the system wouldn't feed that information back to the lighted A/C switch in the cabin. If the light is off, it means the control panel thinks you've turned it off.

I'd probably start with a faulty switch.
 
Check your condenser for cleanliness and check subcool delta on the liquid line before adding refrigerant. Overcharge is very bad too.

Also check cabin filter (if so equipped) and the airbox for debris.
 
Last edited:
Originally Posted By: TWG1572
I was driving my '08 Nissan Frontier this weekend and noticed that the AC was intermittently turning itself off. It was blowing cold air and suddenly I'd notice that the air was warm again. I'd look down and the "on" light was no longer illuminated on the AC button. Pushing the AC button didn't do anything, but messing with the fan knob seems to reset it and the AC kicks back on again. The fan is blowing the whole time. I'd not noticed any issues with it cooling up to this point, seemed to be doing fine this summer.


My Sienna was doing the same thing, working fine until it didn't, and the LED in the A/C button would go off. I traced it to a bad compressor clutch, for the most part it would work when cooler outside but when it was hot it would not engage properly. There is an "engaged" sensor in the clutch and it knew when it was not working.

You can check it out yourself if you can catch it when the light is not illuminated. Looking a the compressor you can tell if the belt is turning the compressor itself or just the un-engaged clutch. For mine it was definitely heat related.

Toyota sold a clutch assembly but it was cheaper to buy a whole Denso clutch and compressor on Amazon. That's what I did and it is working fine now.
 
Also sometimes there is a relay to control the clutch (which can get burned out and give the same symptoms), but on my year Sienna there was not.
 
Funny you mention this. My coworker has a 2008 Frontier also with the A/C having just quit as of today on.
Must be in the air. Sorry I can't help further.
 
Originally Posted By: Hokiefyd
I don't think it's low on refrigerant. And the reason I don't is the system wouldn't feed that information back to the lighted A/C switch in the cabin. If the light is off, it means the control panel thinks you've turned it off.

I'd probably start with a faulty switch.


What he said. I would pop the hood open and see if the compressor is running while its blowing the warm air.
 
I just started noticing it on Saturday, and it's turned off 3 times in about an hour and a half of driving. Next time it does it I'll try to get off the road and see what I can see on the compressor.

I'll also try and confirm exactly what I have to do to get it to reset. Right now, it appears like the AC button, the temperature knob, and the knob that controls the setting don't impact it. This AM, when I turned the speed control down to "1" it kicked back on. I think that's the same way I got it back on Saturday.

Based on some of my reading on the Frontier forums, there is some sort of blower motor resistor on these trucks that can cause wacky symptoms when it goes out. Most people lose fan speeds, but I read a couple posts where people had lost AC at certain fan speeds but sounded like the fan was still working. They were in the minority though, so I'm taking their diagnosis with a grain of salt. I'm not sure how the AC system and that resistor would be electrically interconnected.

Good reminder on the cabin air filter. I need to check it. Replaced it this spring and pulled a mouse nest out. It's possible the prior resident decided to move back in.
 
Some A/C compressors like my Ford truck need proper "air gap" between the plates to properly engage and when you turn on the AC. They come with a stack of various washers or shims to keep the proper gap as they wear. Mine was .047 when it quit engaging. I think its now set at .025 after removing a shim. Too little gap and the plates will stick and ruin your AC. Google AC clutch air gap. It can really fake you out if you gone through everything else and its a easy fix.
 
Make sure your refrigerant charge is correct first, then diagnose the other issues if the problem isn't solved.

Does your truck have a clutch operated fan? A/C problems often happen if the clutch doesn't engage properly. If the condenser isn't cooled properly, the line pressure will rise, and then trip the high pressure switch. The compressor will disengage for a short period of time once the high pressure switch is triggered.
 
Brief update: On the way home last night, I decided to head down the path of checking the easy stuff first and then work down the list of more challenging things.

I figured the refrigerant charge was probably one of the first things to check, like several suggested. I debated grabbing an AC manifold set on the way by Harbor Freight but decided to roll the dice and get the can w/the gauge on it. Probably a bad decision in retrospect. Anyway, I hooked the can up and it showed in the high 20's for pressure. According to the instructions, I should have been at 40-50 at the ambient temps we had. Excited that I had potentially found a contributing factor, I followed the instructions for charging the system. I can report that the refrigerant container emptied, but the pressures never came up. Dunno what's going on there. I'm assuming either a leak, or it's really, really low on refrigerant and one can made no difference. This is the part where my limited experience is showing.

It did cut out on the way to work again this morning. The only thing I can do to get it back on again is to turn the fan speed to 1. No other buttons on the climate control panel do anything. I was on the beltline, so I was unable to whip over and check the compressor clutch. I did not hear it cycling though.

At this point, I'm feeling inclined to take it somewhere to someone who is more comfortable diagnosing this problem than I am. Unless everyone's advice is to buy some actual AC gauges and keep pumping refrigerant into it until I hit recommended pressures. That I can do.
 
Last edited:
Originally Posted By: oilpsi2high
fail for using can gauge


I used one with success. But I guess I'm a noob for doing so *sigh* Well, success until it was done masking the real issue with my AC. Let's say I had prolonged success with it.
 
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