AC Quit

[Bigfish95971]

03,(corrected but the same) Tahoe with auto air and basic rear air.
AC ran on defrost all winter. Went out this week and NO cold at all. Have determined the following:
Clutch is not working.
Jumping pressure switch plug did not help. one side of was hot with 4.8v.
Static pressure was in the normal Green range just fine. NO evidence of past leaks.
I from O'reilly's that there are two ambient temp sensors if the front of the truck and one may be related to the AC working or not.
Today I also noticed that the compass an temp in the mirror went crazy today, sometimes I worked sometimes it was off, sometimes it flashed some symbols and maybe 188 something then off or correct, kept going back and forth.
Have not been able to access the clutch yet, Can I hot wire it for a test?

Is it one of these sensors the clutch or what. Is an OBDII code reader of any assistance with AC issues?

I am new here but have been on Dodge Cummins diesel forum for years and have done extensive writing there on my 99 Dodge with 766kMI on it. But do not know much about air beyond basics. 69 year old retired and full time fisherman.

Any thoughts . thanks in advance.

 

[OR VietVet]

Welcome to the forum.

Did you check the a/c relay in the under hood fuse/relay box? In all likelihood there is another relay in the box that is the same type of relay. Likely has the same numbers on the top of it. Switch them and see what happens. Pay close attention to the a/c relay when you pull it out. Is it real easy to pull out or do you have to work at it/wiggle it to get out? Easy means there is likely not a good connection at the a/c relay female connectors in the box. The exact same thing happened to my neighbor about 5 days ago. I crossed the low pressure switch and nothing happened. Had R134A in the system. When used last was blowing cold. I swapped the relays and nothing happened. Then I took the relay in the a/c slot and wiggled and twisted and the clutch activated and a/c started to blow cold. Sounds like you do have a fuse/relay problem. Even with an empty system, crossing the connector at the accumulator low pressure cycling switch, should activate the clutch if there is power. 4.8V is not enough.

 

[Bigfish95971]

I figure it was a 5 v system so4.8 should be good, I figured. Relay was tight no corrosion, switched with a known working one from from washer pump, same PN. All related fuses in both panels good, tight and clean. Can the clutch be accessed by removing the skid/brush l under front end? Can clutch be ** wired for a test? Do you know anything about those two temp senor and the corrospnding mirror reading?

 

[Bigfish95971]

After doing some more reading I find is 2 TWO ambient air temp sensors. I just replaced 1 and fixed mirror only. My understanding is that the other one behind the light is the main issue, Will have to do it tomorrow if available at store.

I also find it needs an instant programing from a scan tool. Mine don't work. Anybody near Yuba City, CA that can help. Can I do it with a cheap scan tool?

 

[nonickatall]

On the compressor there is a connector with 2 pins. I you attach there 12V your clutch will engage.

But first check if you air conditioning is engaged. You see that on the snow symbol at the control.

Most air conditions quit service when the are in lack of refrigerant.

 

[Bigfish95971]

When I turn the air on the snowflake comes on then goes off. Won't stay on. I have read several places that temp sensor is the issue, but it needs programming after replacement.

I was only 115* today so could not work a lot nit.

 

[Bigfish95971]

I know a guy on my Dodge forum that is building a Dodge in Germany, was in Ukeraine before war.

 

[nonickatall]

When I turn the air on the snowflake comes on then goes off. Won't stay on. I have read several places that temp sensor is the issue, but it needs programming after replacement.

I was only 115* today so could not work a lot nit.

That seems that the air conditioning detects an error. Are you sure that you have enough refrigerant in the system?

Again, I would apply 12 Volt to the connector at the compressor. That is the easiest check. Because then your compressor clutch engages and if you then have cool air in the car you AC is mechanical okay. Next thing is the pressure switch, next thing is the compressor relay.

Where did you read that a temperature sensor can make that problem and that it needs to be programmed? I never heard that...

I think, if the temperature sensor has a shortcut, and the air condition control decides to go in error mode, you can read that as error for sure.

So I would read the errors from the car first.

 

[Bigfish95971]

Is a basic OBDII all I need to program new sensor.? It is my understanding the bad sensor blocks Jumping the pressure switch to turn on the clutch. So I will try the clutch jump it I can get to it, Any trick to get to it?

 

[555hp]

04 Tahoe with auto air and basic rear air.
AC ran on defrost all winter. Went out this week and NO cold at all. Have determined the following:
Clutch is not working.
Jumping pressure switch plug did not help. one side of was hot with 4.8v.
Static pressure was in the normal Green range just fine. NO evidence of past leaks.
I from O'reilly's that there are two ambient temp sensors if the front of the truck and one may be related to the AC working or not.
Today I also noticed that the compass an temp in the mirror went crazy today, sometimes I worked sometimes it was off, sometimes it flashed some symbols and maybe 188 something then off or correct, kept going back and forth.
Have not been able to access the clutch yet, Can I hot wire it for a test?

Is it one of these sensors the clutch or what. Is an OBDII code reader of any assistance with AC issues?

I am new here but have been on Dodge Cummins diesel forum for years and have done extensive writing there on my 99 Dodge with 766kMI on it. But do not know much about air beyond basics. 69 year old retired and full time fisherman.

Any thoughts . thanks in advance.

Compass mirror temp jumping is likely due to bad solder joints in the mirror (mine were at the connector, pretty common). You need to read the real pressures on the low and high side to diagnose the AC. Given that age, you likely need a recharge (and possibly a new compressor if >200k). I have a 2003 and topped off the AC twice in its lifetime.At 155k miles, the compressor is starting to get tired (AZ heat) but still works.