S14 A/C questions...

[candela]

1995 240sx, stock everything.

Ok ive read about 10 threads from NISTECH's advice about a/c problems. Most relate to the compressor running intermitantly..etc From what I have read and what I know here it goes:

My compressor turns on and runs fine. My condensor fan turns on and runs fine. All switches, blowers and everything works as normal. My a/c used to be perfect and work very well (blow cold). One day it stopped and worked as normal accept the temperature never got cold at all! Everything STILL works fine, no leaks... nothing. So i went and bought recharge kit w/inline gauge on it. With car running and a/c on full blast the low side pressure shows that its full. However it is constantly 100* out so maybe its not relly full and it just needs to be recharged, i just didnt want to overfill it and have build up issues.

I just cant imagine how it woudl stop one day with no noticable effects. Does anyone have ANY ideas to try or check? I DONT have pressure gauges, but im not to bad checking electrical stuff and i got a new multimeter ive been wanting to use Thanks,

[NISTECH]

make sure your air mix door is functioning in the heater box.

[candela]

I only have a crap *** hanes manual. I know the filter thing/catch pan and blower motor are the closes to the outside and then teh heater core is to the left/center of the car from there.

Is this "mix door" inside the heater core or blower assembly? I assume its in the heater core and I probably have to drain coolant and what not right? Is there any other way aside from this mix door that coolant/heat could be pre mixing with the oncoming air? Thanks for the response...

[NISTECH]

You need to look at the lever that operates the temp door. this door diverts air in the heater box across the A/C evaporator or sends it across the heater core. If that door is not moving from heater or is only partially moving it will send air through the heater core and warm it up. You need to besure that door is fully moving from one stop to the other.

[candela]

Ok well I pulled EVERYTHING apart (basically entire dash) and am a little unsure about what I am looking at.

I made sure that the valve in the engine bay (the one that lets water/coolant into the heater core, i think its called the water ****) was working properply, and it is...

I pulled everything apart underneath the dash and used every switch I could see and everythign is functioning as it should. However there is ONE valve. Its got a plug going to it with a wingle purple wire behind the radio ( i took it out to ). It has a plastic clip that turns via a small square shaped motor or somethign that has that single wire going to it. Everything I tried I coudl NOT get it to move at all. I dont know what its for but the wire that goes to it is coming off of a seperate harness (main radio one) as opposed to the one directly off of the A/C control unit. Anyhow, I turned it manually and everytime i did that it woudl go back to the spot it was previously in. So i figure maybe it has somethign to do with somethign else like cruise control or the wipers or something...

Sorry for the long post. As I said I only have a hanes manual so I dont knwo what i am looking at at all. I dont know where teh temp door is, but like I said every lever and switch I could see seemed to be working fine. Maybe the one that isnt moving IS the temp door, who knows... Any other suggestions? Thanks!

[NISTECH]

that is your Bi lever door motor. It controls the direction of air flow from on vent to the other by the push buttons. [either defrost or dash vent or floor]

What kind of internet connection do you have and do you have yahoo messenger?

[candela]

i have cable and i only have AIM and MSN...

I just DL a pdf type of FSM for an S14 and read threw i a little bit. I am really thinking that the only thing it can be is that air mix door; however the pics shown on teh manual I have is very vague and I cant tell where it is.

my AIM/MSN = noahrexion

Thanks

[NISTECH]

I was gonna file transfer the entire 95 service manual HA section. I have it on PDF as well. The purple wire though controls the outlet direction not the Air mix door.

[candela]

So where is the door in relation to that? Am i close? :p

[NISTECH]

Yea your in the ball park. You cant actually see the door cause its inside the box. but you can see the movement of the door at the motor. The door motor is on the drivers side of the heater box near the bottom.

[candela]

Motor checked to be fully functional ( I feel dumb I never looked on the drivers side :p ) Its definetly turning all the way and coming to the ends of each metal bracket. So I assume as long as its working and that lever going to the door is moving, that the door is working. Its also pulling the cable to the water **** all the way as well.

Do you have any other ideas? Thanks for the help this far!

[NISTECH]

You are going to need to get some guages on it ,no way around it at this point, your controls seem to be working fine and your compressor is on. So you either have a leak somewhere or a pressure issue with the expansion valve.

[candela]

One last question then...If it is an issue like this with something internal, does it usually occur instantly? Cause it seemed like one day it worked and the next day it did not. I guess Ill have to take it somewehre. Thanks for all the help NISTECH, its appreciated very much!

Austin

[NISTECH]

Yea it can happen, If you took a rock in your condensor and it cuased a leak it would be almost instant, if you expansion valve bacame restricted it would also be almost instant. Basically what your looking for on the guages is for the low side pressure to be high and the high side lower then normal. this would indicate a restriction in the expansion valve, if both sides are low that would indicate a leak. basic rule of thumb is the low side pressure should be pretty close to outlet temp in degrees.

[candela]

I think Ill try to rent some gauges from autozone or something and see what I can get. I dont think I have a leak cause like I said I checked with the cheesy gauge that was inline with the freeon bottle I bought and it showed it at a perfect (highest part of perfect) level.

I assume its like filling w/ freeon, so I have to have the car running at nomral operating temp and run the a/c while I am checking. Thanks!

[NISTECH]

you check the pressures with the car running at 1500 to 2000 rpm,A/C on ,in rec mode, blower speed on hi, drivers window open and all doors closed. you should see something around 30 psi on the low side and 160+ psi on the high side

[NISTECH]

depending on outside temp your readings could be slightly higher.