DIY A/C Check and Trouble Shoot

[dlynes]

Hey guys,

can anyone recommend or post good DIY Check and Trouble shooting guide for A/C?

Yes I know BrianK is the go to guy for CCU fixes but I'd like to do what I can to check and see if it's something I can fix before I send my CCU off or at least make sure that's whats needed.

I have had my 98' for 8 years now and I have never known my a/c to blow cold air.

It blows air but does not blow cold air. I can still adjust the temp and air speed and the fans turn out.

I have recharged it twice and injected dye to test for leaks but not sure if I ever had anyone check it out.

my carfax said I had dealer inspect a/c but I do not remember results or findings (ill call dealer and inquire).

Thanks so much!

PS I've just ignored it bc I've always feared the worst but after all these yrs i'd love to at least look at it and see...

 

[Briank]

Not blowing cold (the compressor not coming on) is almost never a ccu problem.

 

[dlynes]

Not blowing cold (the compressor not coming on) is almost never a ccu problem.

thanks!

 

[dlynes]

bump

 

[Briank]

If you have proper Freon charge then there is something keeping the compressor clutch from kicking in. Could be a simple as a the clutch wire is disconnected or the belt is missing. Do the condenser fans run ?

 

[dlynes]

If you have proper Freon charge then there is something keeping the compressor clutch from kicking in. Could be a simple as a the clutch wire is disconnected or the belt is missing. Do the condenser fans run ?

thanks brian,

yes the fans turn on.

I'll pull all my service records and see what's ever been done.

For life of me, I've never remembered the a'c working in my 8 yrs of owning it.

however, I found a thread where I said it worked once. I've always been keen on fresh air and never used A/C so I just wrote it off and dealt with it.

 

[Briank]

If the condenser fans run the signal from the ccu is getting to the fan control unit so that takes the ccu and fan control out of the problem. Can you hear the compressor clutch click?

 

[dlynes]

If the condenser fans run the signal from the ccu is getting to the fan control unit so that takes the ccu and fan control out of the problem. Can you hear the compressor clutch click?

ill have to play with it and see...maybe I can video it and see if you can hear anything.

I do hear something click when i turn it on and off but that's just based on memory and after 8 years never working, I rarely try...

 

[dlynes]

If the condenser fans run the signal from the ccu is getting to the fan control unit so that takes the ccu and fan control out of the problem. Can you hear the compressor clutch click?

Brian,

How do I know if the condenser fans are running (if it blows air or not)?

when I switch modes and/or change the temperature, I hear a consistent "popping" noise.

No cold air blows and the air temp feels the same from both the driver side and passenger side.

It has been probably 3 years since I recharged the a/c but even then, it did not blow cold air.

thanks so much,

 

[dlynes]

diagrams:

 

[dlynes]

I followed the instructions on the "troubleshooting the CCU" under the wiki files..

http://www.nsxprime.com/wiki/Troubleshooting_the_Climate_Control_System

I tried the first test but no lights were left on...
I tried the "functional check" 3 times and everything was tested..each stage appeared to go thru fine proving the "doors and mode switches are working OK"

 

[nikey22]

not to derail the theme of the post, but "exercising" the A/C is a must in my opinion. That means turning it on a few times (even in the winter time), just to get the oil and lubricants circulating throughout the system.

same goes for the ABS, near winter time, small patch of ice in the middle of no where -- hit brakes, ABS kicks in.. parts are lubricated.

 

[dlynes]

not to derail the theme of the post, but "exercising" the A/C is a must in my opinion.

yea that would have been smart to do.

going forward ill remember that but at the moment I am still at ground zero.

 

[Briank]

Brian,

How do I know if the condenser fans are running (if it blows air or not)?

when I switch modes and/or change the temperature, I hear a consistent "popping" noise.

No cold air blows and the air temp feels the same from both the driver side and passenger side.

It has been probably 3 years since I recharged the a/c but even then, it did not blow cold air.

thanks so much,

The condenser fans are up in the lower corners of the front bumper. They are easy to hear when they are running.

 

[dlynes]

The condenser fans are up in the lower corners of the front bumper. They are easy to hear when they are running.

Thanks Brian,

I tried to listen for it but the radiator fan turned on.

I guess if I turn the a/c on with the engine off, as long as it I do not let it stay on too long, it the radiator fan should not turn on yet.

Ill check tonight.

thanks so much!!

 

[dlynes]

I am going to try the following and see what happens...

All you guys need to do to figure out what's wrong is this
1. Turn on AC
2. See if it's blowing cold
3. If not check fuses
4. If blown replace fuses
5. If still not blowing cold dye the system
6. Check for leaks
7. Replace leaking parts
8. Re-oil with ether oil
9. Change to r134

I'm sure there may be a step of listening to the compressor kick on but I can't hear anything when my cars running.

In my personal experience my fuse was blown, I drained the system which had old r12 in it. Oiled and charged myself. Costs about $60 total...

 

[dlynes]

I followed up with my dealer that's done all my work on my car since I have owned it and it looks like they replaced the clutch and compressor on my car.

they did not pull the records but based on memory they think they said after they recharged it and filled it with dye and they believe they were not getting a signal...

They were able to by-pass it directly by the wire and bypass the ECU and they got signal.

so does this obviously sound like I need to check the ECU?

When I ran the 2 a/c system checks from wiki files, no errors popped up.

I can not hear if the fans turn on so I need to figure that out.

 

[dlynes]

If the condenser fans run the signal from the ccu is getting to the fan control unit so that takes the ccu and fan control out of the problem. Can you hear the compressor clutch click?

Brian,

I have the car on jackstands and I can see and hear both fans in each front wheel well on and spinning.

Should the compressor clutch click the entire time or just during engagement?

My friend looked and he said he could not hear it but I have no idea what I am listening for...

 

[Briank]

Any time the ccu is calling for cooling the condenser fans should run. The compressor should also be running unless the Freon pressure is to high or to low or the engine coolant is to hot.

 

[dlynes]

Any time the ccu is calling for cooling the condenser fans should run. The compressor should also be running unless the Freon pressure is to high or to low or the engine coolant is to hot.

So at this point,

where do I start?

I just got a multi-meter so I can check the fuses and go from there.

Any other recommendations?

thanks for everything!!

 

[Briank]

I would say you could try swapping the fan control unit with a known good one. Other wise you need to check the signals going to the fan control unit with your multi-meter.