A/C problem. Compressor won't turn on
 

Like the title stated, my compressor to the a/c won't turn on. I haven't used the a/c for awhile (maybe 2/3 months until I tried to used it today and I don't hear the compressor turning). I checked all the fuses (one under the dash, 2 under the hood). Any ideas on what else to check before I have to buy a new compressor. Thanks.

It wont turn on, unless you have enough freon in the system. Most likely it leaked out and you need a recharge. Get it recharged and see if activates or not. Most likely its just not charged enough.

-matt

That could be the problem too. It took a while to get cold the last time I used it. I'll check on that tomorrow and hopefully that'll be the quick and painless solution. Thanks Matt!

Hmm.. checked the freon leven and it seemed fine. One thing was when I bypass the compressor sensor(?), the compressor didn't turn on. I did hear a click somewhere in the engine around the brake boost area but if you bypass the sensor, shouldn't the compressor turn on reguardless of the freon level?

Also, I checked for codes and (07 02) showed up. "Three Way Catalyst (right bank)". What is this code mean? I doubt it relates to the A/C problem but just curious on what the code is.

Once again, any information would be greatly appreciated.

Scratch the 0702 code out. I found it in the stickies.

I had a similar issue, but it was with ground on the A/C fuse under the hood. Something went out... and the only way I could get the A/C to work, was to ghetto rig it (I had a wire touching one point to the other) You'll hear a click, when the compressor comes on. You can tell when its working cause you'd normally be getting warm air... once you "hard wire" it. It should start blowing cold air. its not the smartest way to fix it.(cause your can short soo many other things).. but it works for a while.. ( I had run a switch to it, cause if you dont remove it... you'll leave the compressor on, even with the car off), soo... ????? just my 2 cents..

Raul

When I "hardwire" it, I hear a click sound like the compressor is trying to turn on but it won't turn on. The click sounds like it's coming from the other side of the engine bay as well (driver side). The air temperature remains the same. I really don't want to replace the whole compressor when it could be a simple fix I'm overlooking.

Just to double check, the harness I need to bypass the compressor is right near the passenger side hood shock correct?

yeah... its like the second fuse coming from the top down...on the left hand side. So you hear a click... does the engine idle a bit more??? Do the fans turn on?? HHHmmmmmm...use a test light... and probe around the ports of the fuse... just an idea...


Raul

I have tested all the fueses with a test light and they seem to be fine. When I hard wire the sensor, I hear a click coming what sounds like near the brake booster area. The fans do not turn on when I hardwire them either. The idle remains the same as well.

:scratch:

then I think your compressor isnt working... I'm assuming its clicking as to (whatever turns it on) but your compressor isnt working... normally in my instances it would come on... the car would idle about a 100rpms more.. (just a tad bit) and the fans would kick in..... ummm any one else want to chime in on this??

Raul

Freon?
 

What number freon should i put in my 97 maxima?

Please email me ASAP b_roadkid718@yahoo.com



Thanks:hs:

R-134a I believe?

Hmm... read some other's peoples AC problem and they got it to work when the fan was on 4. I tried that and still nothing from the compressor. Anything else I could have overlooked or try out?

Here's something strange today. On this hot/humid day, I tried the AC midday after driving for a while and the AC turned on like normal. I got cold air and everything. Tried this out a couple times following it and it still worked. BUT later that evening when the temperature got colder, the AC did not turn on again? What does this mean? Electrical problem? Loose wire?

Sounds like it. Have you checked the AC Clutch Relay?

I had the same problem on a dodge i sold and it turned out to be the relay. I dont have that problem on my 4th Gen Max but im pretty sure its gonna be the relay.

One quick and getto way to check the relay is when the problem is happening try and knock the relay with something and see if anything happens. Also try and disconnect it and check the prongs for corrosion but make sure you disconnect the battery before you disconnect it.

Are you guys referring to the relay on the passenger side? The square blue top one? If so, I tried swapping it with the Horn relay on that side since it was the same size and everything and it was the same results. AC did not turn on. It was just odd for it to turn on yesterday when the weather was hot and stopped working when it got cooler that evening.

I'll check around for loose wiring underneath the relay.

Make sure the Fan is turning on too.

I'm having the same problem. I developed a slow freon leak as last summer ended, and today I got it refilled for summer but the compressor won't come on.

I thought the compressor had a sensor to protect it from running with no freon, so I didn't worry about leaving it empty over the winter. Now I'm worried I screwed myself and wrecked the compressor, but the fact is it *does* have a "non freon" sensor, right? Is it likely to have burned outself out with no freon in the system?

I tried the fuses and relay with no luck, but haven't done detailed eletrical troubleshooting. I'll make sure I do that or a shop does that before shelling out for a new compressor. Hell, maybe the cavemen at the service place just didn't add enough freon or something.

The fan's do turn in when the AC works but it remains off when the AC stops working. It does kick in as a high idle fan too I believe but that doesn't change if the AC works or not. It is almost at random on when it wants to work or not. I have tried knocking on the relay a few times and wiggling it but no effect.

All fuses should be good since I checked them all and even swapped out the relay with the horn relay.

Freon level seems normal as well but I can't be 100% sure that is not the problem unless I get the high presure and low pressure guage.

Just buy a new one.

A new what? Compressor? It seems like an electrical problem is it not?

You're the most helpful person yet... you should get an award

how are you checking freon level without a high/low pressure gauge?

better to get a new clutch if its not turning on then to play with a compressor parts and sensors.

If the engine is cold, when the AC button is turned on, will the fans also turn on even if the compressor is not engaging?

I don't have access to a guage that will messure both high and low at the same time. Those are a bit pricey. I can probably see if I can get one loaned to me or ask some place to check it out for me. I used one of those 'kits' that came with a can of freon and measure the easist place (low pressure?). Probably not the best way to check but it's better than nothing.

I have not tried it yet when the engine is cold. I will try it in the morning. I know that when I try to turn the AC on and if it DOES turn on, then both fans are spinning. Other than that, both fans are off regardless of AC on/off or fan speed (unless the high idle kicks in).

To my understanding, the fans are on whenever the a/c compressor is engaged since the triple pressure switch sends the "ON" signal to the cooling fan relays whenever it also sends the "ON" signal to the ECU.

Check your refrigerant level. The triple pressure switch is there to protect the compressor from excessively high/low refrigerant pressures by opening the circuit. The fluctuations in ambient temperatures might be affecting the pressures that the switch sees.

Ic ic... will get my hands on a high/low pressure guage soon.

Problem solved - idiots didn't put in enough freon
 

My compressor problem is solved, at least. The cavemen at the oil change shop I went to *said* they put in 1.5 lbs of refrigerant, but apparently cavemen aren't very good at reading gauges.

Went to a recommended radiator/ac shop and they found only 1/2 lb in the system. Recharged with 1.5lb, and the compressor kicked in just fine.

Hmm... I'm hoping that is my problem as well. Thanks for the input. I really got to find time this week to get the proper guage to check it.

Last resort, I can take it to a shop and ask them to check my freon level and add/remove if needed.

You know the idiots at the shop may have put 1.5 pounds in and one pound leaked out...? Hope that's not the case...

re:shop idiots
 

Actually I *do* have a leak which is why I needed it refilled, but it's a slowish leak. The lube shop morons said the compressor wouldn't turn on 30 seconds after they "filled" it. If the leak was that bad, there'd have been a hissing white cloud of freon jetting out of something. It'd be coming out as fast as it went in, and they'd never have seen any pressure on the gauge.

The evidence is that my leak is in my evaporator. According to the a/c shop and the Nissan dealer, I'm like the 3rd person ever to have a Maxima evaporator go bad -- lucky me!

I would take to a mechanic you I trust. I had the same problem, took it to two different mechanics for diagnotic and repair. One of them told me I need a compressor, and the other one told me my compressor and condensor were bad. I paid them the diagnotic fee ($60 total) and went to another mechanic who found the problem was a loose valve. AC dfor now is working fine.

I took it to my uncle who has been working on cars for over 15-20 years as a mechanic and also my brother who's been working on cars for roughly 5 years.

They told me that since the AC can turn on and it does get cold fairly quickly, the problem is not the compressor. It is either an electrical problem somewhere, relay problem, or improper freon pressure. Hopefully it'll be a freon pressure level so it's a quick fix and I can spend my money else where on the car.

Ten years too late replying to this thread, but this is correct for my 5th gen at least. I had an issue with one of the hoses to the compressor, I'm now in a low pressure situation. Compressor and fans won't come on when I start the AC. If I jump the AC relay (left side engine relay box) the compressor clutch engages and the fans turn on to low. It would seem that the low pressure switch prevents the compressor from engaging as well as enabling the cooling fan relays. I wish I knew that before checking every fan wire/relay/fuse thinking my fans were dead :)

The very purpose of the low pressure switch is to prevent the a/c compressor from running if the there is not enough refrigerant (R134A) in the system. The reason for this is that there also is oil in with the refrigerant to lubricate the a/c compressor. If you run the compressor without refrigerant, you are running it without oil and the compressor will self-destruct. If the low pressure switch sends a signal to the ECU, the ECU will not turn the a/c compressor on.. Since the a/c compressor is not being turned on, the ECU will not turn the fans on as they are not needed.

Measure your R134a pressure with it off there will be pressure there if charged...Then it need be either just add some freon or bypass the low pressure switch and measure your pressure..

:jump: