There doesn't seem to be a forum that is applicable to the air conditioner so hopefully a few people see this in here.

I have a brand new 2003 Xterra SE and find the air conditioner to operate very strangly, and unlike any other car I've had and unlike the manual says.

After toying around and testing it appears the 2003 A/C has been changed to operate in a semi-automatic mode, with the compressor coming on through some strange voodoo combination of the temperature control and who knows what else.

In my vehicle at least, it appears the A/C button is little more than a sort of manual overide to force the compressor to come on, although it doesn't always work that way. In addition, there are times that the temperature control is on hot, and the compressor will run for a while then shut off.

According to the manual, the compressor should come on in the defrost modes, but I'm seeing it come on it ALL modes, at seemingly random intervals. One thing that is certain though is that turning the temperature nob all the way to cold turns on the compressor.

I've talked to two dealers about this and they claim it is the correct operation of the new system. I find it hard to believe that in the new models there is no way to simply get outside air unheated and uncooled.

Anyone have any insights/clarifications.

If your A/C button is OFF, and your RECIRC button is OFF, you should get outside air without the compressor kicking in... UNLESS you're in Defrost mode. In Defrost mode, the compressor will kick in because that's the most effective way to defrost your window (dry air).

The rest of the time if the A/C button is ON, the compressor WILL kick in and out as it has to cycle to keep the air at a given temperature. Most newer cars work this way. Think of it as a cruise control alternatively gassing and letting up to maintain a relatively constant speed.

If it's coming on in all modes, then it's broke, and your dealer is clueless.

PNUTMNM,

--- quote ---
The rest of the time if the A/C button is ON, the compressor WILL kick in and out as it has to cycle to keep the air at a given temperature. Most newer cars work this way. Think of it as a cruise control alternatively gassing and letting up to maintain a relatively constant speed.
--- end quote ---

This is how I understand it SHOULD work as well, however on my vehicle it is doing this independent of the A/C button. I've now had two different Nissan service departments tell me this is the correct operation on the 2003 and that it was changed from 2002. Personally I think they are wrong and my A/C button is stuck in the ON position even though the light still turns on and off.

Do you by any chance have a 2003 or have access to one to test this. On my vehicle simply turning on the fan, and turning the temp down to cold engages the compressor ALL THE TIME.

Thanks for the info..

This might account for things...

http://www.nissan-techinfo.com/nissan/TSB/Nissan/54301.asp

Brent

Its funny that you found that since I tried to yesterday and couldn't. The dealer gave me a copy of the Service Bulletin which he said he'd never seen before yesterday. I wish I had it electronically because its actually quite funny.

Essential it says, and I'm paraphrasing...

...
On 2003 and later models...
If the mode selector is set to defrost or foot/defrost AND the outside air temp is about 36F, then the compressor will run with the mode selector switch in any position
...

Really, I'm serious. It says in defrost mode, the compressor runs in all modes. I asked the dealer what that meant and he didn't understand it either. I asked him what the A/C button did and he said that as he read it, the A/C button didn't do anything on 2003 models.

I smell a serious issue or recall coming. That service bulletin makes no sense and is written like its trying to explain away a problem.

Sorry, I have an '01. I agree with you, that service bulletin sure is a horseshit way to explain things.

khs,
Send me an email address and I can send you the TSB.

Just a quick note. I have a 2002 and the compressor kicks on and off when the AC button is active. JFYI. And is it common to hear the compressor kick on and off in the cabin? This is my first truck and in my previous cars you couldn't hear it but in the X I can. Is that normal?

I can hear it when I'm idling, but not while I'm cruising down the road...

What I hear is a slight 'thump' noise when the compressor clutch engages. At least that is what I think I am hearing.

After sending my vehicle in for service for the second time in the first week, the word from the dealership is that on the 2003 Xterra the compressor does indeed run all the time. Simply turning the temperature control to cold result in cold air through the vents, without the A/C button being "ON". Any time the fan is turned on, the compressor runs.

I haven't yet had a chance to talk to anyone with half a brain but at this point all indications are that the A/C button has no function at all on 2003 Xterras. In addition the manual's description of heating/cooling/defrosting is completely contradictory to reality. I'm supposed to get some official explanation from Nissan Consumer Affairs in the next couple of days.

Needless to say I'm pretty disappointed with this whole situation and wish I had kept my 2001 Pathfinder.

Oh puh-leeze, this is enough to sour your on your Xterra and make you long for your old Pathfinder? Gimme a break...

Brent

Give YOU a break Brent? I'd feel the same way if it was me. Perhaps not so much that the compressor runs all the time (if that's the way it was designed to run), but not getting a straight answer from anyone and Nissan. That, coupled with a very contradictory owners manual, it screams of a "problem" that Nissan is trying to sweep under the rug.

If I'd have traded my '01 X for an '03 X and had the same problem, I'd pine for my old reliable as well.

I would be pretty upset if the A/C compressor was on all the time. Performance suffers and gas mileage suffers.

There is no reason it should be on all the time.

Agreed, it's a dumb change, but it's a bit extreme to make someone wish they hadn't bought the vehicle...

Brent

As mentioned above, its more the run-around I'm getting that is disappointing. Other than this A/C issue I really like the vehicle. I do miss the 250 HP of the Pathfinder though. It will take some time to get used to.

My local dealer is starting to open up and hint that he thinks the A/C shouldn't work this way as well. However he also says he's talked to Nissan and it IS working as designed for 2003. He also admitted this morning that several people have similar complaints. This is at a pretty small dealership so I'm guessing this is only going to get bigger.

The dealership I bought the vehicle from wants me to bring it in to them to take a look. Since its about an hour away from me I haven't yet. I've gotten the same run around on the phone from them as well. It appears dealers aren't in the know about this new "correct" operation.

From what I've experienced and been told by the dealership, the A/C compressor on 2003 models runs anytime the engine is running and the fan is on. I'm still waiting to hear from a Nissan engineer. I'll post another upate when I have more info.

The dash switch isn't even shown in the 2003 wiring diagram so I don't know what it does. The diagram leads me to believe that whenever the fan is on at any speed the ECU decides when to run the compressor.

I wouldn't like this either, especially with a manual transmission.

That would certainly reinforce my theory that the A/C button does nothing but show a pretty little light. Even the service manager sort of shrugged when I asked what the A/C button does.

If you have it electronically, is there any chance of getting a copy of that wiring diagram? On a related note, where did you get it yourself?

Thanks,
Kurt

It would make me think twice about buying one.

Having the compressor kick in, or disengage when you don't want it to isn't fun.

click me

I have no idea of where this came from.

Well the plot is thickening regarding the compressor operation.

Nissan Consumer Affairs finally got back to me and informed me that on the 2003 models, the compressor runs anytime the fan is on and this is by design.

The funny part is that thanks to the nissan's service manual website snafu, I have found a page in the manual regarding checking the magnet clutch engagement (which I interpret as the clutch to the compressor) when the A/C button is on or off.

After I gave the service manual page number to the Consumer Affairs rep his tone changed a little bit and said he'd have to get back in touch with engineers. At least he admitted that it was confusing. For anyone interested its on page MTC-44.

Everything in print seems to indicate the A/C button works as expected. Everyone I've talked to says that the compressor runs all the time. This is quite odd.

Kurt

This is not a unique situation. The 2001 manual still shows the 2000 fog light wiring and they are NOT the same.

I have a 2003 and I can't recall ever hearing the compressor engage when having the button off (other than defrost). What I can attest to is that there is a definate difference in having the button on rather that off. When on the cold setting with the a/c button OFF, it gets very hot inside the cabin. Turning it on definately forces COLD COLD air out from the vents.

WOW.. I'm floored now.

I have had two dealerships and Nissan Consumer affairs tell me that the compressor runs all the time when the fan is on. Apparently your vehicle isn't working correctly. I really wish mine wasn't either.

I actually just talked to my local dealership for the 4th time. They informed me all they could do was do what Nissan said, and Nissan said it was working properly.

On a related note... When you show a page out of the service manual to a service manager he gets a little snotty and sarcastic, at least in my experience..

I'm going to be taking the vehicle back to the original dealership later this week with a comment regarding lemon laws and see what happens.

Kurt

Go to the dealership and test the 2003 Xterras on the lot.

Sometimes the simplest solution is the most brilliant! I actually tried the compressor on one at lunch. Behold, COLD air came out of the vent and the compressor kicked in with the A/C switch in the OFF position.

I don't know how bringing up lemon laws is going to do any good. If Nissan says that is how they work, how are you going to invoke the lemon law?

I agree with Ian, before you go accusing the dealership of selling you a faulty vehicle, ask to test the A/C on a few 2003's on the lot.

It looks like between Tungsten78 and PNUTMNM that there is some conflicting information. If both of these people are correct in what they've experienced then that certainly lends itself to my theory that there is some problem in the 2003 line.

Testing other vehicles is certainly a valid way to check the "normal" operation, but if all of Nissan's documentation explain the A/C working one way, and it actually works another (and most would agree its very wacky to run the compressor all the time) then that to me says design/assembly flaw. Especially when nobody can explain in a clear manner what the "correct" operation is.

Ironically the salesman that I purchased the car from called me in the past 2 hours to just check in. After explaining the situation to him, he agrees that the compressor should not be running all the time and he's heard nothing about that on 2003 models. I'm taking the vehicle to them this friday. They are about 30 miles away and hence the reason I didn't go back there to start with.

What's really funny is the service manager at the original dealership has told me via the phone that the compressor does indeed cycle on/off in all modes; although mine doesn't ever cycle, just runs on.

At the very least Nissan needs to send out some clarifying information to dealers and service centers. That "service bulletin" they sent out has a lot of people confused.

Kurt

I've found that to be true as well. We're supposed to be blissfully ignorant for "the system" to work properly.

Could simply be a mid-production change, not unheard of. The 2000 models had some not-insignificant changes a few months into production.

Brent

Yep. They changed the tail-lights midstream in 2001 as well.

I happen to know the service department manager (Hugh Stevens) at Feldmann Imports fairly well due to a mutual quest to discover the "leaf-spring mount, underbody rust problem of 2000" together. He's a straight shooter and I respect his judgement. He also volunteered to replace my wife's Maxima hood because the paint "looked funny." He's not afraid to challenge Nissan and he's always worked with me on any question I've had.

I called him on this A/C deal, just to get his take and to put a bee in his bonnet to come up with a definative solution. He knew about the "issue" and personally believes its a problem. He agreed to contact his Nissan technical representative who bulldogs these sorts of questions for their dealership. He should call me sometime tomorrow.

I don't know if this will yield any further depth to the well of knowledge we already have, but it couldn't hurt. Besides, I trust the guy.

Thanks for that effort PNUTMNM. It's nice to know that at least someone out there in Nissan land seems to admit there is an issue floating around.

Hopefully some clear explanation will surface soon. If there was some production line change it would be nice to hear about it.

Really I doubt that Nissan will ever put in writting that the compressor runs all the time as designed. That just creates more questions than it answers.

Kurt

Thought I'd double check to be sure, but since the Compressor model used is NOT a variable capacity type (like the pathys' maximas 350's) then I'd tend to agree that constant operation is not appropriate.

If the compressor WAS a variable capacity (or whatever Nissan's term is for a compressor that varies it's own outlet pressure as needs dictate, and does not use clutch cycling to control output pressure) then constant operation would not be an issue, as the compressor would use whatever engine power it needs, versus the drain a standard type causes..

Also, since the X AC system is NOT the fully automated climate system found in the Maxima's, there shouldn't be a need for constant operation, I'd think.... those systems run the AC all the time, and it's more or less required for the system to maintain a perfect interior temperature.

If Nissan did it to prevent interior fogging, they should fix the ventilation systems, not compensate by using the AC... from what I see (which is admittedly much less than a nissan engineer should know).

-=RB

(FYI - from what I see, the AC control head requests AC from the PCM, and the PCM actually controls clutch operation. If you were going to hack, I'd start with the line from the AC head to the PCM, not by killing the clutch power elsewhere, since the PCM will try to compensate for the idle drain if it thinks the compressor is supposed to be on.)

I tried switching the A/C button on and off and I could tell a difference in the air coming through the vents. When I had the A/C button off, the air blowing was cool, but felt somewhat humid. When the button was on, the air was cold and felt dry. Not sure if this helps with anything...

Thanks for the input PHAT. When you turn on the A/C (pressing the button that is) do you hear the compressor engage? It's very noticeable at idle as a click/thunk, which is the compressor clutch engaging. On my vehicle that only occurs when the fan is turned on or off.

If you know which pulley to look at you can also check if the compressor is running visually. That stopped the dealer really quick from telling me that click noise was just the fan turning on.

Kurt

OK, I toggled the switch again and I seemed to notice a slight drop in the RPM's when the A/C switch is turned on. Also, I hear a slight noise when I turn the switch on - the noise isn't very loud, as in, if you weren't listening for it, you'd probably not hear it. I'm not exaclty sure which pully it is, but if you can describe it, I'll check it out.

When standing in front of the vehicle, the compressor is the top-right most pulley. The pulley will always spin, but the clutch that is in front of the pulley will engage and spin when the compressor is on, and be stationary when the compressor is off.

On my vehicle simply turning on the fan, with the A/C off, engages the clutch. It sounds like at least 2 other people are reporting this happens with the A/C button.

Kurt

I have a 2003 4x4 SE Xterra.

Here's what I tested:
Turn off recirculation, Turn off A/C, Turn on Fan, humid air comes out.

Turn on A/C, hear slight noise, air turns cooler and less humid. Turn off A/C, air turns humid and less cold.

Turn on recirculation, Turn off A/C, Turn on Fan, humid air comes out.

Turn on A/C, slight noise again and the air turns cooler and drier. Turn off A/C, air gets warm and humid.

It seems to be working properly for me.

For anyone still interested, the story is getting more refined....

I just returned from another local dealership service department and finally someone is on my side.

After explaining the whole story, and including the info I've gathered from people here, the service manager agreed we should try a few vehicles so off to the lot we went. After testing 3 different 2003 Xterras the results were interesting.

On 2 XE (manual) models the A/C button did indeed control the compressor function as explained in the manual. In addition turning to defrost engaged the compressor as explained in the manual. These 2 vehicles were operating, what I would consider, correct.

On a SE model, along with my own vehicle, the A/C button did not have any discernable function and the fan control alone would toggle the compressor on and off. The defrost mode appeared to have no impact on the compressor.

The service rep agreed this is strange and nothing they've encountered before. He also agrees the recent service bulletin does not apply, since it explains the operation we saw on the XE model exactly.

At this point his only idea is a difference between XE/SE or manual/automatic. However at least one response on here was from an SE owner with the "correct" operation.

They are now escalating the issue to Nissan techs to figure out what is going on. From the existing technical documentation there is no difference in A/C units between models, etc.

Getting someone to agree there is an issue is half the battle. I'm glad the first half is over.

Thanks for the feedback to everyone on here.
Kurt

Strange...keep us posted. I am going to say something to my service manager about it also to make sure he is aware. He owes me a favor!

To add more data: My 2003 X was built on 9/2002 and is an automatic.

PHAT has also a SE (though with a SC). Maybe you should try an older SE and see if that happens?

I mentioned this to my service manager, and he hasn't heard about it yet. I told him there have been lots of complaints and he said that he is going to call Nissan and check into it.

The saga continues. I just heard back from my friend Hugh, the service manager at Feldman Imports. It gets trickier...

According to Hugh, who spoke with his Nissan technician, they (Nissan) changed the logic of how the system works on the '03. Regardless of whether or not you have an XE or an SE, this is how the system is SUPPOSED to work:

With the engine running, turning the fan output selector switch to "defrost" or "defrost and foot" mode will activate the compressor and a clutch will kick it in and out as is necessary to keep the air dry and at temperature. IT WILL STAY ENGAGED AS SUCH regardless of how you alter the fan output selector switch OR the A/C switch at this point. So, no matter where you want your air to blow, the compressor will continue to kick in and out regardless of the position of the A/C switch.

The only way to "reset" the system, is to set the fan output switch to "top vent" or "floor vent" ONLY, turn the truck OFF, take the key out of the ignition, and restart the truck with the switch in that position. Then, the A/C switch will operate as it should (unless you flip over to Defrost, where the whole thing starts over again).

I don't know if I'd like it this way or not. If you use the defrost in the morning and forget to switch it to "floor" or something, the compressor will kick in for your entire drive home unless you stop the truck, switch out, and restart.

Weird. Hugh also said that the owners manuals were not changed to reflect this change to the system. He tried 6 trucks on his lot and they ALL worked this way.

If this post is confusing to you (its hard to write up such weird logic), send me an e-mail with your phone number and I'll give you a call so we can discuss it further.

PNUTMNM,
What you've explained is exactly how I read the Service Bulletin that was sent out a few weeks ago, basically saying once you engage defrost, the compressor stays on until the car or fan is turned off.

While I think this is a bit odd, it's at least documented. This morning at the dealership, we confirmed that two 2003 XEs did indeed work this way. Once you turned off the vehicle, and back on, you once again had control over the compressor.

Unfortunately my vehicle, and another SE on the lot don't work that way. The compressor is a function of the fan only.

For anyone who has a 2003 that is working "properly" but doesn't like the defrost issue, I found a writeup that explains how to disable it. I've already poked around and found the electrical switch but haven't implemented the change yet, since it doesn't do anything on my SE anyway. If Nissan ever gets it working properly, I'll then disable the defrost/auto-compressor switch.

The writeup is at...
http://nissanoffroad.net/frontier/how_to/auto_on/default.asp

Kurt

Well best of luck khs. I don't think there is much of a correlation between the '03 XE's and SE's. I have an SE/SC and it operates exactly like the manual says. I do have to turn the fan to off to disengage the clutch after using defrost. Otherwise, it's always off unless I explicitly turn it on via the switch.

I don't think it has anything to do with the XE/SE either. I'm really starting to think that maybe there was some bad batch of A/C switches or wiring assembly that forcing the compressor to stay on.

This has certainly turned into a good mystery. I can't wait to walk into my local dealership (the one that basically told me to go somewhere else) with the solution and let them know I'll be referring everyone I know somewhere else.

khs: Sorry I haven't had a chance to check out the pully yet to see if it's engaging and disengaging properly - I have been busy moving (from Austin, TX to Houston, TX). I'll try to check it out tomorrow and let you know something. However, I always keep my vent mode swtich set on the facial vent position, and according to what I gathered from PNUTMNM, this explains why I think my A/C switch is working like it should.

I will confirm what PNUTMNM said. I just recently noticed this on a trip. I had the defroster on for most of the trip (mostly by accident) and noticed that it was definitely becoming pretty cold inside, I knew that the defroster uses the AC, so I switched it to regular a non defrost selection and it was still very cold... well I stopped for something to eat, got back in and the air was now coming out warm and humid, so I just rolled down the windows (my preferred cooling method).

on my 2003 x if i turn the ac on i cant turn it off no more. i push the ac button the light goes off but the ac clutch stays on. i have to shut the truck off and restart it then the clutch is off. but wow my ac is ice cold.

I think the last two posts actually explain what Nissan considers to be correct operation. According the what I've read and experienced in other vehicles, the compressor will come on when you turn to defrost. It will STAY on even after you turn off of defrost to other modes, even if the A/C button is off. To "reset" the system you have to turn the vehicle off and back on, then the A/C button should function normally until you turn to defrost again. I think this is rather strange, but at least it is documented this way.

I WISH mine worked this way. Unfortunately in my vehicle, and at least one other new one, the A/C button seems to be hardwired ON, even thought the light toggles on and off. Personally I think its a simple matter of some wiring being messed up, but I get the explanation that this is normal.

For anyone interested, there is a simple fix to disable the defrost from engaging the compressor. There's just a small switch behind the mode selector dial that engages when the knob is turned to defrost.

I've already experimented with this switch and unfortunately it affects nothing in my vehicle. Neither does the A/C button for that matter..

Kurt