Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner
1 - 10 of 10 Posts

·
Registered
2002 chevy trailblazer_ltz
Joined
·
26 Posts
Discussion Starter · #1 ·
My AC is acting up and I need some opinions/help.

The story is I recently got my condenser and accumulator/dryer replaced due to a crack in the condenser that leaked out my refrigerant. Since I have gotten it back this cycling issue has popped up. Basically after driving for some time the compressor turns off and no cold air. The condition is made worse on hot days.

I already switched out my low/high pressure switch hoping that was the issue. No dice its still doing it.
Yesterday I shorted the connection on the switch and now it seems to run fine.
This leads me to believe that the pressure in the system is high, the new accumulator/dryer is somehow broken, or there may be some sort of clog in the system.

Since hot days make this worse could it be that the pressure is towards the high limit and when the system gets hot enough the refrigerant expands enough to raise the pressure over the limit? I dont know how the limits on the switches work and if they are that tight or not.

If its a clog I have been told I will need to replace the accumulator/dryer again since that is most likely where the clog is taking place. Is this the case?

What sort of damage can I do to the system if its running with high pressure?

I hate AC problems because its one of the few things I cant do much about myself since I can not evacuate the recharge the system myself.

Any help is greatly appreciated.
 

·
Registered
2002 chevy trailblazer_ltz
Joined
·
26 Posts
Discussion Starter · #3 ·
I have left the jumper in place since last night.
It has been working with no cut outs since I installed the jumper.
It has not been as hot out though since its cloudy out today.
 

·
Registered
2002 chevy trailblazer_ls
Joined
·
2,232 Posts
My AC is acting up and I need some opinions/help.

The story is I recently got my condenser and accumulator/dryer replaced due to a crack in the condenser that leaked out my refrigerant. Since I have gotten it back this cycling issue has popped up. Basically after driving for some time the compressor turns off and no cold air. The condition is made worse on hot days.

I already switched out my low/high pressure switch hoping that was the issue. No dice its still doing it.
Yesterday I shorted the connection on the switch and now it seems to run fine.
This leads me to believe that the pressure in the system is high, the new accumulator/dryer is somehow broken, or there may be some sort of clog in the system.

Since hot days make this worse could it be that the pressure is towards the high limit and when the system gets hot enough the refrigerant expands enough to raise the pressure over the limit? I dont know how the limits on the switches work and if they are that tight or not.

If its a clog I have been told I will need to replace the accumulator/dryer again since that is most likely where the clog is taking place. Is this the case?

What sort of damage can I do to the system if its running with high pressure?

I hate AC problems because its one of the few things I cant do much about myself since I can not evacuate the recharge the system myself.

Any help is greatly appreciated.
There are separate low pressure and high pressure switches. Which switch did you short? The high pressure switch is located on the compressor, the low pressure cycling switch is on the dryer-accumulator. The high switch will shut it down if pressure exceeds 350 psi as I recall. Does it cool OK? If the fixed orifice or screen was clogged it wouldn't cool very well if at all.

Or another possibility is they overcharged the system with refrigerant doing the repair which is causing excessive pressure. Also, your symptom sounds like a weak fan clutch not moving enough air through the condenser which plagued these for 4 years until they came up with an "improved" design clutch to move more air. Yours being a 2002, has the fan clutch ever been replaced?
 

·
Registered
2002 chevy trailblazer_ltz
Joined
·
26 Posts
Discussion Starter · #5 ·
I jumped the switch on the dryer-accumulator. At first I thought they were separate but my repair manual says nothing about another switch on the compressor. It also says that if you jump that switch and the compressor works that your pressure can be either high or low.

When it is cooling it cools great.

My fan clutch is original. I know about this problem but even at highway speeds this happens. I thought the fan clutch issue was more of a startup and stop/go issue?
 

·
Registered
2002 chevy trailblazer_ls
Joined
·
2,232 Posts
I jumped the switch on the dryer-accumulator. At first I thought they were separate but my repair manual says nothing about another switch on the compressor. It also says that if you jump that switch and the compressor works that your pressure can be either high or low.

When it is cooling it cools great.

My fan clutch is original. I know about this problem but even at highway speeds this happens. I thought the fan clutch issue was more of a startup and stop/go issue?
Check your manual again for a high pressure cutout switch on the compressor high pressure side. It will have one, otherwise nothing to prevent excess pressure from destroying the compressor or bursting a hose.

If happening while going down the road, likely not the clutch. Could be undercharged causing low pressure and cutout. Below 20 psi or so, low pressure cycling switch will cut off compressor, then turns on when pressure rises to about 45 psi.
 

·
Registered
2002 chevy trailblazer_ltz
Joined
·
26 Posts
Discussion Starter · #7 ·
The thing is I just got the thing recharged when I got the new condenser. I can check the pressure. I will look again for the high pressure switch on the compressor. I would think if the charge is low that it wouldnt cool very well even when it is working.
 

·
Registered
2002 chevy trailblazer_lt_ext
Joined
·
365 Posts
Sounds like it's under-charged. If this is the case, remove the jumper before you damage the compressor and have the pressures checked.

Did they bring the system down to a vacuum before they charged it back up?
 

·
Registered
2002 chevy trailblazer_ltz
Joined
·
26 Posts
Discussion Starter · #10 ·
No I just want to make sure I have an idea of whats wrong so they dont go and try to charge me for doing things that wont fix it. I have had very bad experiences trying to fix car ac problems in the past. Not this car and not this shop but now Im paranoid. Ill make an appointment and bring it in for them to check out.

They did do a full evacuation and recharge after they changed the condenser.
 
1 - 10 of 10 Posts
Top