Air Conditioner not working?

There are two separate problems, the AC issue sounds like the system needs to be charged here is a video to help show you how.

https://youtu.be/uZrQCGwXfek

and

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

Please run down these guides and report back.

Rear A/C vents blowing cold air while front vents blow warm air. What could be causing that?

Good afternoon.

First, you need to have the pressures checked for the AC system. We need to be sure the pressures are correct.

The other thing is the blend door actuator in the front. Can you hear the mode door move when commanding heat and cold?

Roy


https://www.2carpros.com/articles/replace-blend-door-motor

Air Temperature Actuator Replacement (Single Zone)

Removal Procedure


imageZoom/Print

1. Remove the driver side knee bolster.
2. Locate the air temperature actuator (6).
3. Disconnect the air temperature actuator electrical connector (7).


imageZoom/Print

4. Remove the air temperature actuator bolts/screws (1).
5. Remove the air temperature actuator (2).
6. Remove the air temperature actuator lever (3), if necessary.

My Uplander's AC doesn't work, I can start the vehicle, the ac clutch comes on, the cooling fans turn on, the ac clutch turns off. No cold air comes out of the vents at all, I checked the pressures and have about 105 psi on the low side and about 365 on the high side.

Sounds to me like the system is severely overcharged. It is easy to get the amount of refrigerant this guide will show you how.

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

Please run down this guide and report back.

That could be the case, because I let my son borrow it for awhile, twice. He might've done that this second time, I'll see.

The first time he had it in the winter, he brought it back in the winter months, and I noticed the cooling fans would come on about 10 seconds after starting it. They would, and still do, the entire time you're driving the vehicle and don't shut off until you turn the key off. So it is exhibiting the same behavior , I'm just not sure of the ac clutch starting or ac pressures because you don't use ac in the winter. Could there be a switch problem somewhere that is the primary reason this all started? It also has rear ac, if that matters.

You may think you don't use AC in the winter but that car is wired to engage the AC compressor whenever defrost is selected because it removes moisture from the air and you can't allow this to happen in it's present condition.

I'll call the Chevy dealer here tomorrow to have it checked out.

I'll make sure I post back on what they found.

I spoke to my son this morning he said he did add some, the last time he borrowed it, which was in the summer. He said he noticed the fans coming on like that in the winter but thought it was normal. With that being said, is there an underlying cause, that would make the fans come on and stay on like that even in the winter? The engine doesn't run hot, it hasn't been overheated, the coolant level is normal in the recovery tank.

Let's just say I go out, start the vehicle, leave the ac off, and all the rest of the blower, defrost, etc. off. What would cause the fans to act like that.

Thank you for replying so quick too, I appreciate it.

There are many things that could cause that from stuck relays to a bad computer and everything in between this guide can help us find it.

https://www.2carpros.com/articles/how-an-electric-cooling-fan-works

Please run down this guide and report back.

For the last year or so the AC has been having problems, It works fine on cool cloudy days or at night, but during the day when it is in the eighties it works off and on, the air will go from upper fifties to eighties or nineties. I checked the low pressure side , when the compressor is running on an eighty degree day, the low pressure is 35-38 psi. The compressor will run sometime sixty seconds then shuts off for about ten seconds. On hot days the compressor will only run for a few seconds at a time. Cool nights the compressor will run continuously and the temperature from the vents will drop into the fifties. I cant figure it out, during the hot daytime it will not cool, after a few minutes driving it will cool slightly but the vent temperatures are about eighty degrees. On old
Fords they had a Freon switch that would switch the compressor on and off if the Freon is low but according to the readings it should have plenty.

Autozone, just scanned it about 10 minutes ago. There were no codes, it has no check engine lights, and I can assure you no one has done any wiring to the vehicle, except GM when it was new.

Hello,

It sounds like the system is low on Freon, it is difficult to tell the state of charge by the low side. Here are a couple of guides that will help you get the problem fixed.

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

and

https://www.2carpros.com/articles/air-conditioner-how-to-add-freon

and

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

Please let us know what happens, we are interested to see what it is.

Cheers, Ken

This is a 2 speed circuit and pretty complex so you're probably going to need a professional to troubleshoot it.

I understand the circuit, but I don't see the logic that tells the ECM to turn the fans on, other than the IPC telling it that the engine is hot.

Is there a sensor that is telling the IPC that the engine is hot located on the engine somewhere?

Looking closer at the engine, the fans actually turn on in slow first after approx. 6 seconds, than the fans go into high speed approx. 4 seconds later. I swapped the relays around making sure the ones I swapped were the same as the ones I was swapping to. They all showed the same symptoms, so I'm pretty sure its not a relay problem for the fans. I unplugged the ac relay and the clutch doesn't engage at all, like it was previously, but it still followed the process it was before.

There is an electronic coolant sensor that the PCM monitors for many functions to include fuel mixture and numerous other components. If you have a scan tool you can look at the reported coolant temps. The fans are not only regulated by temperature. The PCM monitors AC pressure also so you could even have a shorted out pressure sensor. That could also be seen with a scan tool.
That diagram only shows the circuit that operates the fans, not the logic that operates them. The PCM controls the relay trigger ground to turn them off and on.

Do you know the location of the ac pressure switch on this vehicle so I could do a visual of it.

Air Conditioning problem 6 cyl Front Wheel Drive Automatic 96000 miles Hello, the A/C in my '07 Chevy Uplander (96,000 miles) has quit working. The A/C light inside turns on and under the hood the Compressor kicks on and seems to be running properly. The low side line is cold and the pressure (checked with one of those cheap gauges on top of a recharge can)(picture below

) shows at the top of the blue "filled" area. However, when I pulled the gauge off the port the refridgerant was green. Is this normal? I have had the vehicle since it had 36,000 miles on it and hasn't been serviced as far is I know.

Hi to diagnose properly need to get a gauge set on system and see what high and low readings are. Look for shop in area that specializes in AC have a diagnosis done $20-$40. Then post results and will advise as to repair.

Here is a guide that will help you.

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

Let me know
Thanks for donate

Is the PCM looking for a normally open or normally closed from this switch?

So I could unplug it and see if the fans act normal?

Hi, I put my (cheap) set of gauges on the system and am posting the pictures from the readings. Low Side: +17 (I hope the makes sense)

High Side: +56.25

Any thoughts on the pressure?

Neither, That is not an open/close switch. It's a 3 wire, 5v reference that delivers a specific return voltage that translates to a specific pressure.

Low should be @ 35psi high needs to be @200psi. readings indicate low charge. Green is a dye placed in system to help ID leaks with use of black light.

Surely its designed to turn off the fans if the switch opens?

I gave you the outer reading on my gauge (marked 134A) the inside marks are PSI. The High side is 210psi and low side is about 60psi. I think I figured out the problem though. It started working after I took the box around the heater core apart. I think that it isn't always directing the air around the heater when I turn the dial to the cold setting.

I vacuumed down and recharged the system which fixed the AC and fan operation! thank you so much for your help.

Yes blend door will cause low side to go up and not cool

Problem was fixed, high pressure switch was bad, switch location is between the radiator and front of the engine. It's about 6-8 inches from the AC compressor.