AC flow not changing when changing mode

[rubberman15]

1999 C5, Coupe, hatchback.



I am not getting any increase in air flow from the AC when I switch between exterior air and recirculation. Passenger side flow seems a little low but okay, but center and driver door flow seem really low. I also notice air from under the dash on the driver’s side. The fan is working and I don't get any messages from the computer. I also don't think the vent is changing when I change the mode. Is it possible the internal vent doors are stuck? Even with the fan on max, the flow is not very good.

Anybody have any ideas on how to resolve this?


Thanks

 

[Patrick]

Rubberman,
I need to ask a clarifying question: when you switch from exterior air to recirculated air, are you also changing the fan speed, or changing which part of the car the air is circulated to? Merely switching from exterior to recirculated air doesn't change the force with which the fans are blowing it around, it simply ensures your air supply within the cabin is being recirculated (useful to quickly cool off the cabin.)

Also, remember that your Corvette will have different temp. settings for the passenger and driver side, which may account for why you notice a difference in air flow pressure between the two sides- the temps may be set differently on your Corvette.

-Patrick

 

[rubberman15]

Rubberman,
I need to ask a clarifying question: when you switch from exterior air to recirculated air, are you also changing the fan speed, or changing which part of the car the air is circulated to? Merely switching from exterior to recirculated air doesn't change the force with which the fans are blowing it around, it simply ensures your air supply within the cabin is being recirculated (useful to quickly cool off the cabin.)

Also, remember that your Corvette will have different temp. settings for the passenger and driver side, which may account for why you notice a difference in air flow pressure between the two sides- the temps may be set differently on your Corvette.

-Patrick

Thanks for the reply Patrick.

I have the passenger setting set in the middle (between red and blue) and the driver side set at 65. I need to put the fan to the highest speed to even get a moderate flow at all on the driver’s side, with airflow coming from the dash vent. The passenger side flow seems to be a notch or two higher though.

I have a feeling the recirculation setting is not working and the interior duct work is not operating. Something else I have noticed is the recirculation mode should keep a majority of the traffic exhaust out of the interior, but does not seem to stop anything.

With the mode on recirculation, at max fan speed, air flow seems like a low fan setting and you can feel air being forced out from under the dash, just behind the cigarette lighter.

I have always noticed a change in the way the system works when switching from exterior air to recirculated[font=&quot][/font], but do not notice anything now.

I have been driving the car throughout the winter using the heater and did not make any changes to the settings, other than for temp and I am wondering if it is possible for things to freeze up? If that is the case, how would I free things up again?

Do you think I should just break down and take it in to the dealer?

 

[DRTH VTR]

There is a vacuum line that runs in the wiring harness under the battery. One common issue is battery leakage and resultant acid damage below the battery. I had the battery acid destroy the vacuum line that is part of the a/c actuating system. This may not be your issue at all, but other people have had this happen as well.

 

[rubberman15]

There is a vacuum line that runs in the wiring harness under the battery. One common issue is battery leakage and resultant acid damage below the battery. I had the battery acid destroy the vacuum line that is part of the a/c actuating system. This may not be your issue at all, but other people have had this happen as well.

DRTH VTR,

If I remove the battery, is that something that is easy to spot and resolve if neccesary? How did you resolve it on yours?

Thanks

 

[DRTH VTR]

DRTH VTR,

If I remove the battery, is that something that is easy to spot and resolve if neccesary? How did you resolve it on yours?

Thanks

rubberman15
Here are a couple of other threads that discuss the issue. The battery has to come out, and the battery tray as well. Then you con look in there and see what is going on. There are more threads in the CAC that discuss this; I found these by searching "battery acid".

I traded my '97 in for my 2002 just after I found this damage. I did not fix it myself.


http://corvetteactioncenter.com/forums/showthread.php?t=61394&highlight=battery+acid

http://corvetteactioncenter.com/forums/showthread.php?t=7116&highlight=battery+acid

 

[Gman]

Seems lots of people are dealing with this climate control system! I just got mine up and running yesterday and it turned out to be the ambient temperature sensor that was causing big problems. There is a test procedure for the doors. I pulled the three fuses ( two in the pass. footwell fuse box and one in the underhood box ), waited a couple minutes and reinstalled the fuses. The idea is to interrupt voltage to the controller. You can also do this by disconnecting your battery. After reinstalling the fuses, I turned the key to the on position to hear the doors open/close. Mine were functioning fine. My problem was that the ambient temperature sensor was shorted and was showing temps of 44 degrees on a 83 degree day. The system was actually trying to bring the temperature up to 60 rather than down. :crazy I changed the ambient sensor and after driving about a minute or two over 50 mph, the ambient temp showed the actual temp and the system began functioning as normal. Ice cold a/c!

If you can't find the fix, you can bring it to the dealer to get a diagnostic for about 70 bucks. The dual zone is pretty much a waste in a two seat sports car, IMHO. Too complicated, too fickle, and too tightly packaged.

 

[RonJ]

My problem was that the ambient temperature sensor was shorted and was showing temps of 44 degrees on a 83 degree day

When you say the ambient sensor, do you mean for the exterior air temp or for the interior air temp?

My AC seems to be working fine, but if I pull codes, I get a DTC that tells me the interior temp sensor is open.

Ron ... :confused

 

[Patrick]

When you say the ambient sensor, do you mean for the exterior air temp or for the interior air temp?

Ron ... :confused

Ron,
The ambient air temperature sensor is a sensor mounted under the hood which reads the exterior temperature. I know this because in February, I had to change it on my Eldorado.

The big question I had about it was why would the outside temperature have any bearing on my climate control system? Well, apparently, it's tied into the climate control by giving it an indication of how hard it must work to regulate the temperature inside the car. Mine had gone completely beserk: it was telling me the outside temperature on a frosty morning after a snow was 128 degrees farenheit, and the effect was it wasn't working as hard as it should have to defrost the windshield and rear window, because the computer didn't think it was necessary to do so.

The good news: it was a $20 part to replace, and took all of five minutes once I got the sensor out of the box.

-Patrick

 

[Gman]

When you say the ambient sensor, do you mean for the exterior air temp or for the interior air temp?

My AC seems to be working fine, but if I pull codes, I get a DTC that tells me the interior temp sensor is open.

Ron ... :confused

I was referring to the exterior sensor, which Patrick explained. You also have an interior temp sensor to the left of the ignition. It has a little grille over it. The two sensors work together to determine cooling/heating needs. They basically tell the system when to turn the blower fan up or down or switch to outside air rather than recirculate. I've learned that if any of the links in the chain are not functioning properly, it throws the system off and weird things happen.

Also, I've learned that the passenger side seems to get better airflow and better cooling/heating. It sounds weird, but it seems GM designed this system to benefit the passenger over the driver. Go figure. My a/c is working exactly like it should and with the passenger setting neutral, the temp of the a/c at the vents is 4 degrees lower on the passenger side with noticeably better air flow than the drivers side.

Does this help?

P.S. Did you try testing the doors? Also, the c/c system should be on recirculate mode when using the auto function on the system. All the recirculate function does is use interior air ( rather than hot exterior air ) to cool the car down faster.

 

[JDC3020]

Ambient Sensor replacment

Hello,

I think I'm going to give this a try as well but not recognizing the location yet since not much time to get under the hood unfortunately.

If anyone still here does this sound like my issue, I guess at least probably so..

- Mine shows incorrect temps occasionally

- Low flow from all vents continuously

- 1-2 time a month the AC button light blinks for 4 seconds then goes off with no cooling..

Thank you much,
jc

 

[XLR8]

Hi JC! I can't help with your cooling issues, but hopefully someone will drop in soon that is better qualified than me.

I just wanted to give the thread a bump to the top of the heap and say hello and

Jane Ann

 

[JDC3020]

Thank you..

Hi JC! I can't help with your cooling issues, but hopefully someone will drop in soon that is better qualified than me.

I just wanted to give the thread a bump to the top of the heap and say hello and

Jane Ann

I appreciate that Jane Ann,

I'm going to try the Ambient Sensor replacement purchased today plus battery disconnect procedures to see what happens in the morning. Clean the contacts as well.

Pretty bad in Dallas with the air running low, the whole system definitely seems to have baffles partially closed.

Air is cool and sensor shows correct temp right now but since I have had the other behaviors before I'm hoping all may be related to the sensor.

1. Current - Low flow from all vents continuously..

2. A couple of times a month AC button light blinks for 4 seconds then goes off with No cooling for 30 minutes..

3. Shows incorrect temps occasionally

I for sure have had water intrusion with a puddle that was a bit more than expected at about 38 mph.

 

[JDC3020]

ACFan still on full but blocked.. Acts like low setting..

My sig was supposed to say 2000 Metallic C5 39,000 miles..

No luck today with new Ambient Sensor installed.

I reset with battery disconnect as well.

No changes still cold air and fans running full but partially blocked ventilation throughout..

I guess I will check under the battery for a problem I did have to get a new one but not sure if I had any leaks at the time probably a little..
jc

Just taking to myself again..

 

[JDC3020]

fans running on full but partially blocked ventilation throughout..

I have 99HVAC codes: B0361H, B0441H

I have some for A1 RDCM, and A0 LDCM as well but I belive those issue started at another time, but were from water intrusion I think to MAF

Any ideas?

I wish I could permanently remove the damn doors in the system..



Mine Too..
2000 Metallic C5 39,000 miles..

No luck today with new Ambient Sensor installed.

I reset with battery disconnect as well.

No changes still cold air and fans running on full but partially blocked ventilation throughout..

I guess I will check under the battery for a problem I did have to get a new one but not sure if I had any leaks at the time probably a little..



​

 

[Junkman2008]

I need a little more understanding of exactly what you're experiencing. Post the exact codes that you show RIGHT NOW and also a detailed description of what happens as you adjust your HVAC. I've had plenty of fun with the dual climate control and will probably be able to help.