Air Conditioning Issue 95 NSX

[rmmnsx]

A/C will works perfectly cool air no issue on somedays and others days no cool air what so ever.
Ran diagnostic test every thing checks good. Started the car today no A/C. Started up later in the day A/C runs perfect.
When the cooling is not working I can still turn heat on.
Compressor works fine turns on and off accordingly in all cases.

Read a lot of threads could not find this issue listed.

Any ideas would help.........

 

[ofdlt10]

ac not working

hope this helps.
the plastic shroud on the outside of the cable that opens and closes the door that directs heat slips and leaves it open allowing heated air in and makes it feel as though air isn't working.
look near the firewall where the cable actuator is located and have someone inside change from heat to ac and see if the cable is slipping.
all it took on mine was an adjustment to place the plastic shroud back under the clamp and tighten it back up

 

[Old Guy]

Does your intermittent operation of the AC occur in all modes of operation or does it only occur in the AUTO mode?

Kaz provided the following information about operation of the climate temperature setting on MIN (and the fan on Auto). It can provide a convenient test of the system. In this mode, all the sensor inputs are ignored except for the evaporator temperature.

MIN temperature (18degC): Fan speed at max unless you set it manually with the right dial.
A/C compressor: Forced to switch On but CCU will switch it Off if the evaporator temperature gets below 3 – 4degC (you can manually switch it Off afterwards but not much point when you want to cool down the cabin).
Mode motor: Force the air to blow out from the VENT position (unless you manually override it afterwards).
Vent motor: Fully open unless you selected manual fan speed or overdriven the Mode.
Fresh/Re-circ mode: Re-circ mode (unless you manually override it afterwards).
Water valve motor: Fully Closed​

Try this mode of operation on one of the occasions that the system is not blowing cold air. It forces the compressor to run and all the sensor inputs are ignored except for the evaporator temperature. You should be getting max cold air in this mode of operation. If the compressor is cutting out in this mode, you might have an intermittent electrical problem - bad connection to compressor or the evap sensor might have a flakey connection or who knows what or some problems with the refrigerant loop. In this mode of operation, as [MENTION=12044]ofdlt10[/MENTION] suggests check to make sure that the heater water valve is fully closed (cable is not slipping).

Is the diagnostic check that you ran the Self Diagnosis test for the CCU? If that is all you did, you should also run the Function Test. I don't think the Function Test is described in the owners manual so you will need to get a copy of the Service Manual to carry out the function test. However, since your problem appears to be intermittent, the Self Diagnosis and the Function Test may be of no value if you carry out the tests when the air conditioning is operating. For the test to be of any value you would have to try them when the air conditioning has failed. Also, the Self Diagnosis can only test the control and monitoring circuits associated with the CCU. It cannot identify problems that are mechanical or electrical problems that are not directly associated with the CCU, its sensors and the control motors (it won't identify a buggered linkage or jammed flap)

 

[rmmnsx]

95 nsx a/c

It happens in all modes...
Yesterday no air ....went through every combination.
The I put the heat in max for a few minutes switched back to full cold air flowing ..... it worked.
Don't know what today will bring...trying to figure out the location of the cable ofdlt10 mentioned.

 

[Old Guy]

trying to figure out the location of the cable ofdlt10 mentioned.

In the front compartment, there are two bulkhead pipes for the heater core that pass through the front firewall. They are located approximately between the brake booster and the blower housing. As I recall, the heater control valve is mounted on the lower pipe. It should be very obvious once you take a look along with the clamp that ofdlt10 mentioned.

Nice picture in post #3

http://www.nsxprime.com/forum/showt...d-a-few-more-questions?highlight=heater+valve

 

[TomCat]

The dryer was plugged (intermittently) on my 1991. $100 fix

 

[Kaz-kzukNA1]

Being as 95 model, if your CCU board was never serviced before, 100% guaranteed to have leaky capacitor issue even if you may think it's fine.
All sorts of symptom but the typical one is that the fan speed control only works when set at max speed setting.
If you are in US or nearby, just send it to BrianK here on Prime.
His site; http://nsxe-repair.com/

This will take the CCU electrical issue out of the possible cause.


As I don't know your HVAC knowledge level or technical background, apology in advance if I'm asking something you already knew.

How did you check that the compressor was working?

Probably you don't have manifold gauge but how was the refrigerant level through the sight glass at the receiver/drier/filter?


There are many factors that could change the efficiency of your a/c system and sounds like your issue is intermittent so diagnosis may not be easy but I would start with the above.


Kaz

 

[rmmnsx]

1995 nsx ac

I went down the wrong path so I had my mechanic trouble shoot the car .
Turns out it was the Air Conditioning Tri Pressure Switch which is bad.
Anybody have a idea were I can find one
[h=1]Switch, Air Conditioning (Tri) - Acura (80440-SL0-901)[/h]or is there a cross reference part out there. Seems like Acura is back order our no longer in stock.

rmmnsx

Being as 95 model, if your CCU board was never serviced before, 100% guaranteed to have leaky capacitor issue even if you may think it's fine.
All sorts of symptom but the typical one is that the fan speed control only works when set at max speed setting.
If you are in US or nearby, just send it to BrianK here on Prime.
His site; http://nsxe-repair.com/

This will take the CCU electrical issue out of the possible cause.


As I don't know your HVAC knowledge level or technical background, apology in advance if I'm asking something you already knew.

How did you check that the compressor was working?

Probably you don't have manifold gauge but how was the refrigerant level through the sight glass at the receiver/drier/filter?


There are many factors that could change the efficiency of your a/c system and sounds like your issue is intermittent so diagnosis may not be easy but I would start with the above.


Kaz

 

[rmmnsx]

1995 nsx ac

[
Found the cross reference most auto stores carry them.

Listed under [FONT=&quot]A/C Trinary Switch[/FONT][FONT=&quot] [/FONT][FONT=&quot]
O'riley & Rock Auto part # 20952
[/FONT]

QUOTE=rmmnsx;1983485]I went down the wrong path so I had my mechanic trouble shoot the car .
Turns out it was the Air Conditioning Tri Pressure Switch which is bad.
Anybody have a idea were I can find one
Switch, Air Conditioning (Tri) - Acura (80440-SL0-901)

or is there a cross reference part out there. Seems like Acura is back order our no longer in stock.

rmmnsx[/QUOTE]

 

[Kaz-kzukNA1]

While it can fail on other production cars, it's very rare for the triple pressure sw to fail on NSX unless you accidentally hit it with something.
Probably having the engine at the back and being away from it makes better environment than other cars.
Still, I won't say it never failed on NSX but just so rare.

Please make sure to order the one with the correct thread size/pitch.
I have never replaced one on NSX but I 'think' the R134a one is in metric and the R12 one is in inch.

You will be forced to evacuate the system before replacing the sw so good time for doing any a/c related service.


Kaz

 

[rmmnsx]

1995 nsx ac

While it can fail on other production cars, it's very rare for the triple pressure sw to fail on NSX unless you accidentally hit it with something.
Probably having the engine at the back and being away from it makes better environment than other cars.
Still, I won't say it never failed on NSX but just so rare.

Please make sure to order the one with the correct thread size/pitch.
I have never replaced one on NSX but I 'think' the R134a one is in metric and the R12 one is in inch.

You will be forced to evacuate the system before replacing the sw so good time for doing any a/c related service.


Kaz

Found out the cross reference they show was incorrect.

Listed under A/C Trinary Switch
O'riley & Rock Auto part # 20952 this listing NOT Correct

Found the correct OEM Part at the thensxshop.com
R

 

[bonhamsurf]

Yes this is an OLD thread, but I'm trying to get my Compressor to work. I don't think it's bad, so before I go out and buy one, does anyone know where the Fuse/Relay is for the AC COmpressor itself? I have a 91 with a converted R32 AC System, and I charged the freon, so I know it's got enough. Plus no leaks. Did the dye/UV light test. Thank you.