I had a problem with one of my manual cc where the hot cold switch wasn't working and stuck on hot. When the fan was off you could feel the warm air coming out of the vents. Remove your glove box then remove the intake sensor and see if cold air comes out of the hole. This is before the heater core so if warm air is being mixed it will be after this hole where the sensor is.

 

You mean remove that little rubber grommet on the black box and see if cold air comes out there ??

 

Yes.

 

I just really want this thing to work. Its litterally blowing 51-55 degree air out of the center vents and I know thats not correct.

I pulled off the plastic under the wheel and looked at the doors operating when I do the test, and they all seem like their moving ok, and 30 still popps up on the diagnosis for the doors. When I turn the system off, and turn it back on, I dont see anything moving under there. I just dont know what else to do here.

-matt

 

Well thats the evaporator box, shouldnt that be ice cold coming outa there ? what will this tell me ?

 

Yes it should be ice cold coming out of there. If it's ice cold it will tell you that one of the doors is staying open allowing hot air to come thru the vents along with the cold air. If it's the same temperature as what comes out of the vents then theres some other problem.

 

This will be the next thing I check tomorrow. I did run all the codes on the Auto Climate control and 30 is popping up for the doors and motors working properly.

 

When your driving at highway speeds and have the temp set on the coolest setting and the cc off is the air coming through the vents cool or warm? Same thing for the hottest setting is the air cool or warm?

Also does the ac blow cold when you first get in the car after it has been sitting awhile so the engine coolant is cold.

Just seeing if maybe your air mix door motor is not functioning properly and allowing hot air to mix with the cold air.

 

Highway speeds = Cool after about 5-10 miles of driving. Not Cold cold. If I set the Auto Climate to 65, it will blow FULL fan the entire way to work to try and catch up. Might kick down to 3rd fan, but blows the same cool air. No where near cold. It will kick down if its a cooler temp out, 65-75 out.

No. Engine coolant temp has no bearing on it. I even went as far as clamping off the upper heater hose and drove like that for about 10-15 miles and made no difference.

The place I just picked up the car from is stating that the system is fully charged and that line going into the car is plenty cold, but the air isnt which makes him think its a mixing door. I really dont think its that though.

 

At highway speeds I was asking with the climate control turned off and no fan on. If the air mix door motor is working properly and the cc was set to 65 before being turned off cool air should be coming through the vents. As with the cc on the hottest setting before being turned off warm air should be coming through the vents.

When your able to pull the glove box and grommet that will tell you if there's a problem with the air mix door motor if the air is cold.

 

Ill test that on my way home.

 

Matty, did you replace the tape on the expansion valve thermal probe? Tape is insulating while the metal clip originally used is thermally conductive.

 

I have the end of Expansion valve taped with two peices of black tape onto the evaporator tube. I have NO metal clip on there...$1 from nissan.

What do you think ?>

 

I'm not sure it's the expansion valve, because with ice cold refrigerant lines, it would seem to be doing its job. No-one asked this yet - do you get drips of water coming out from under the car, particularly on humid days? Just checking that your evaporator drain is not clogged.

My wife's max is pretty similar to yours. I have reasonable pressures and replaced the compressor/dryer/ex valve/condenser a couple of years back. We saw an improvement but really it's not the same as modern day a/c units.

 

I would go ahead and buy that clip.

 

You think that would have a major effect on the system blowing cold

 

The expansion valve operates by that probe. If the probe is not at the right temperature, the valve would not operate correctly.

 

You would see that problem if you looked at system operating pressures. The suction line (low side) wouldn't be ice cold as Matt say's it is.

Even if the servo motors are moving correctly, that doesn't mean the doors are really moving. I just replaced a mixing door on my Ford Explorer. It was broken inside the HVAC unit, actuator worked just fine but the keyway shaft on the door had split.

I really think you need to look inside the HVAC unit and verify the doors are swinging correctly. I didn't have the pull the entire system out of my Ford, it was a common problem and thanks to an Explorer forum I was able to cut a hole in it, verify the problem and replace the door. It took me just over an hour and the door was $8 bucks. I can now regulate the temp in my truck and the A/C is ICE COLD.

 

I got to thinking. Don't you have our emanage or j & s sageguard mounted to the top of your ecu? I thought I remember seeing pictures of that.The air mix door motor and linkage is at the bottom of the cooling unit and either of those two could be in the way.
Maybe the problem started right after you installed those?

Have you removed the glove box and grommet yet or checked out the temp differences on the highway?

 

Now the million dollar question is, where is this door ???
When I run the diagnosis on all the doors and I look on the Drivers side, all the doors swing freely, but what door is the air mix door ??

Seems like I dont get cold cold air when its HOT out. Like today, its 70's and the air is cold coming out.

I have my emange on the floor of the pass seat. Theres nothing mounted on top of the ECU. I do have wires running through the arms of the doors on the drivers side, but nothing is getting in the way of the operation.

I couldnt do it on the way home from the work the other night cause it was cold. Today, I def will look into that and get back to ya.

 

Tom,

What was his air temp like when the door wasnt operating correctly ??

-matt

 

Alright on the way to work today, bright sun and about 85 out, never really got cold.

I tried turning the entire system off, got cold air at my feet. Then I turned it to 85, econ, heat blowing, and turned it off, and got heat on my feet. So it seems like the doors is working if thats a good way to test it.

Got to work after running the a/c for 35 min, and took the grommit off on the front of the evap box. This is air AFTER the evaporator and before the heater core, and it was the same temp as the vents. Actually seemed a bit warmer but thats only because it was a small stream of air coming out.

 

Yep your air mix door motor is working properly.
It has to be something with the evaporator or expansion valve. I would get that clip for the probe. Maybe you got a bad expansion valve or the PAG100 clogged it?

 

I just dont know where to go from here. Should I have the system evacuated, pull the evaporator box out, install that clip. Then drop the compressor and completely drain the system ? Then spend another 100$ on a new dryer ? Do I replace the expansion valve as well ??

 

First step would be to install the clip. You wouldn't have to remove the evaporator box to do that. Just remove the blower motor and you should be able to reach it. Also every temp probe I have seen has been wrapped with foam. Do you still have foam around yours?

 

No. I have nothing wrapped around the probe but tape thats holding it to the evaporator. I dont think Ill be able to reach it with it still in the car and be able to install the clip and foam.

 

You will be able to install the clip for sure. I'm not sure about the foam. You may be able to remove the bottom portion of the evaporator box as well.

 

You think the clip will make THAT big of a difference for lets say roughly 10 degrees ?? What does the clip actually do ??

To remove the lower half of the box, you need to unsrew the bottom half and theres no room to fit a screw driver in there.

 

The clip just holds the probe to the low pressure line. Without it it may not get an accurate reading. I'm sure the foam is there to keep the reading accurate or the blower motor may give it a false reading. Does it blow any colder when the fan is on setting 1 compared to 2,3,or 4?
Your probably right about the box. The back screws would be hard to get to.

 

Nah not really. Just a smiggin over warm, I would guess its blowing 51-54. Then without the sun blairing, prob gets to about 46-48.

Im gonna order the clip and some O-rings from Nissan to break everything apart. Ill bring the car to get evacuated, bring it home, drop the compressor, and the evap box out. Do I order another dryer too ??

Where should I get the foam from to wrap the probe ??

 

.

 

Well there you go. Where did you find that info?

 

http://www.aircondition.com/tech/que...ses-in-Foam%3F

 

While I have the system open do I drop all the PAG100 oil out of the compresser and install PAG46 ? Do I buy a dryer too ? When I get the system evacuated, does ALL the R134 and Oil come out ??

 

what do you guys think ??

 

You can reach the expansion valve probe by dropping the lower half of the evaporator box.

The mixer door is just after the evaporator box in the air flow.

Let's hold on the thermal (freon) side until you try these cheaper fixes.

 

What am im buying the wrap the probe (tar tape and foam ) ? Am i buying that clip as well from nissan ?

 

Yes buy the clip from Nissan. They may even have the foam. Heres some pictures if you have forgotten how it looks.

 

K thanks...might need to pull the box. Ill see tomorrow but ill order the clip tomorrow and get that on the way.

 

SVI30,

I was reading an earlier thread and you said you didnt have any of that foam or tar stuff on the probe ?? And your a/c is ice

-matt