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Air conditioner code?

pktwatch

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Emporia, Indiana
I turned on AC on this spring and nothing! I tried jumping the low pressure switch and the compressor still did not turn on. I noticed that the indicator light on the power button for the AV will flash 3 times when I try to turn it on and found this info in the owners manual:

#(Air Conditioning): Press this button to turn the

air conditioning (A/C) compressor on and off. When

air conditioning is selected, an indicator light will come

on to let you know that the air conditioning has been

activated.



Pressing this button when the outside temperature is

too cool for air conditioning will make the air conditioning

indicator flash three times
and then turn off to let you

know the air conditioning mode is not available. If the air

conditioning is on and the outside temperature drops

below a temperature which is too cool for air

conditioning to be effective, the air conditioning light will

turn off to let you know the air conditioning mode has

been canceled.


I first tried to run the AC when in Tennessee a couple of weeks ago when the temp was in the mid 70's so I don't think that the outside temp was the issue.

Does anyone know if I could have a bad temp sensor or what other problem I might have.........I AM going to get the battery and charging system checked because I know that they can cause problems in these computer controlled trucks but it has not showed any signs of problems in those systems.

It is a 2007 Avalanche with the manual controls.
 
It ended up being the low pressure switch, was bad and it let all of the freon leak out.....new switch and freon and all is well again!
 
Where is the low pressure switch? I have a freon leak in mine and the dye doesn't show up anywhere easily visable so I am looking for anything that doesn't require pulling my dash apart... ;)

Mine doesn't throw a code and the light stays on. Just doesn't get cold.

Rodney
 
Lo press siwtch is on the accumulator very near the lo pressure fill port.
Simple 2 wire connector on it.
 
On my '07 it's back by the firewall on the right side....
 
Not trying to be a PIA here, just wanted to educate you cats a bit.
Freon, DuPont's brand name for their R-12 ( dichlorodifluoromethane) refrigerant isn't in anybody's AV. It hasn't been in any factory vehicle since 1993 and has been illegal for any licensed tech to use to recharge a system since 1999.
Our AVs have Flourane, or R134a (Tetrafluoroethane) as our refrigerant.
However, this may soon be illegal to recharge systems with as well, as the European union is in the process of passing legislation to stop the use of R134a and replace it with  HFO-1234yf (Tetrafluoropropene)(no brand name has been established as it is only currently available commercially and not for retail sale) and if so, North America surely won't be far behind
 
It's common for the low pressure switches to fail, the diaphragm inside fails and it slowly leaks out. $20-$50 depending on where you buy it.

As far people calling the refrigerant Freon, yes it's not the correct name but more of a generic name people use that aren't in the know, like calling a copy of a document a Xerox because they were one first copy machine manufactures.

January 1, 1996 was the date automobile manufacturers in the US could no longer use R12, most switched over before that date.
 
Since my truck doesn't seem to know it doesn't have enough 134a in it I have been considering opening up the system and replacing all the obvious stuff like o-rings and any sensors that tend to go bad. Then have the system vacuumed and recharged and see if it holds. 

Not sure what else it could be since no dye has been showing up on my truck. I really don't want to pull the dash apart and replace the unit in there until I have tried everything else. My truck was cold the first two summers I had it. The third summer I needed to charge it and it lasted almost all season. Haven't done anything with it since then. The AC button lights up and acts like it is running but I get hot air out of the system with it set on cold.

Rodney
 
Could be the blend doors under the dash. If you think it's low on 134a look at the low pressure switch #31 on the accumulator/drier #28. If  you see oily residue and dirt around it, it could just be the low pressure switch. The diaphragm fails in them and the charge slowly leaks out. Easy to change out because there's a schrader valve under it so you can remove it with out allowing air into the system. It seals with an O-Ring so it does not have to be much more than hand tight. If you've never charged a system then take to a shop or pick up 134a at the auto parts and top it off.

 

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Well I can tell you when the system is charged back up that it is really cold... So Yea I suspect since the system is NOT tripping out that it is a sensor issue.

I don't have any issues with heat in the winter time so I wonder if the blend door would have anything to do with that?

That is a nice colored picture too by the way..

Rodney
 
If the system is charged up and it blows cold air then it's probably not the blend doors.

The pressure switch will still work once it's charged and it will slowly leak over time. Look at and around the switch for any residue. Not saying that's the problem just trying to eliminate one.
 
The low pressure IS a common problem and that was what was wrong with mine. It confused me because i was getting the light flashing 3 times when I turned it on, I thought it was some electrical code.
 
Just tried it today and the AC light stayed on as long as I ran it (15 mins) but never blew out cold air.

But yea if I charge it up it will form ice on the windows if I kick it up to high... lol...

Still debating on buying all the o-rings and replacing them all. I know those go bad over time too.
I hate to run the system low though because I know if I let moisture into the system it could kill the compressor. More worried about killing that then anything else...

Rodney
 
I would run a can of leak detector through it and look at it with the UV light. The compressor should not run with low freon.....I know, I know it's not freon. So is the compressor clutch engaged?
 
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