A/C Help Needed

[Frotax]

I need help with this A/C on a 2003 2500 HD.

 

This thing blows cold air from the get go. Its charged.

 

When 110 out, you can start it and have cold air right now.

 

Problem is, I cannot figure out how to keep the AC pump kicked in.

 

After a while, it kicks out, and blows hot air. Nothing will kick it

back in, except time(hours of running, or shut it down, die, lay in the shade

and restart and go, and hope you get where you need to go before it kicks out.

 

How can I get some 1970's technology on this thing and make it so it stays on even if its its -40 below zero outside?

 

I want this AC on, and to stay on until I say so.

 

45,000 dollar truck and can't even have AC.

 

Ive heard others say its d**n near made them get rid of the truck, and buy something else.

 

My neighbor has the same problem(2005). Dealer says" nothing we can do, you just have to suffer it out"

 

They have checked everything, and nothing works.

 

His blows cold air right from the start too, then kicks off and death starts to creep on as it gets hotter and hotter in the cab.

 

Is there a way to make the pump stay on till you turn it off, or is there a way to disable this automatic crap?

 

What makes the pump kick off? I mean, if the outside temp is showing 115 and youre wringing wet in the cab, shouldnt the Auto deal say "A/C On?

 

Someone surely can figure out a workaround for this, right?

 

I've called dealers and one said, "We need the business, so bring it in, we will evacuate and recharge it, bla bla bla, but it probably wont change anything"

 

Well, duh, it blows Ice cold when the pump is on.

 

Help!

 

 

Thanks, Gabe

[masterp2]

Your post tells me you are in a very humid place, and the dealer has tried various solutions, but your coil is icing up nonetheless.

 

I would suggest. using the AC on a more moderate level, recirculate only, to keep the humidity at bay.

 

If some of your charge were removed that would also possibly solve the icing issue. Yes Icing, the evap coil ices up, the pressures go wacko (because air can't flow thru the coil) and she shuts down.

[masterp2]

Where are you that it is 115 and that humid?

[Frotax]

Where are you that it is 115 and that humid?

 

<{POST_SNAPBACK}>

 

 

 

Theres no humidity in the Eastern Sierra /Nevada.

 

Today its 102 and the humidity is 12%.

 

Everyone in CA, NV, AZ has this problem.

 

Last week the neighbor was in Havasu, 120* about 8% Humidity.

 

No A/C Until they stopped, ate lunch and took off again.

 

Weird thing is, sometimes the A/C will stay on forever like it should.

 

Other times, it cools the truck down, shuts off and you're screwed until it

decides to come back on, or you stop for a while and restart.

 

This problem occurs no matter what the outside temp/humidity.

 

Even at night in Spring, Fall etc.

 

The dealers are aware of this.......most say, "You have to suffer"

Others will do plenty of BS work to "Fix it" Of course they know

nothing, nothing changes but will do more work.

 

My closest dealer said they needed business and to bring it down and they would

do all kinds of work "But it won't do anything"

 

Everyone knows this problem exists.

[mmmikkke]

Just got back from a 400 mile round trip through Michigan's lower peninsula today. Temperature around 90 degrees all day, nearly froze myself out with the a/c. 2005 2500HD with manual a/c controls. No problems. So it's not "everybody" who has this problem.

[dizzy]

Sounds like your coil is freezing up like the others said, doesn't have to be 115F for that to happen, and I've seen it happen in 12% humidity, in fact our humidity rarely gets over 20% when you need A/C. Once the coil freezes up you have no air going through it. Sounds to me it is doing exactly what it should do when that happens.

 

But keeping the clutch engaged is the very last thing you want to do. My 2005 won't stay in recycle mode, it automatically kicks back to outside air after a few minutes.

 

I would check the temp sensor/thermostat or just take it in and have it serviced especially if you have recharged it yourself. If you have to keep it engaged all the time to keep it cool, then it is not functioning at its best.

 

I would also pressure wash the radiator/evaporator, could be full of bugs. I don't think the newer R-134a units work as good as the old R-12 units did when it comes to cooling.

 

It has finally cooled off for us, it has been 112-115F for the past 2 weeks.

[Frotax]

I think you guys dont understand.

 

Engine Cold. engine hot. Start up, blows cold right now.

works awesome.

 

Then, out of the blue, kicks off and nothing but hit ambient air.

 

if you stick it out, it'll kick back on.

 

Or you can stop, shut down the rig. Wait.

 

Start up and go.

 

The compressor does not need to stay on to keep it cool.

 

It blows ICE COLD. But not if the AC pump isnt working.

 

I know 30 people in the SO Cal/AZ/NV area that all complain

the same exact thing.

 

Even the dealers have no idea, but they do know there is a problem.

 

Thats why I would like to find a way to control the AC

by using On/Off Like a 72 Chevy.

 

This no AC when its 110 degrees is BS.

 

Like I said, you can sweat it out, till it decides youve suffered long enough

or shut her down and wait.

 

Sometimes, for no reason, the AC will stay on for a 3 hour drive, like

its supposed to.

 

Even the service manager at the dealer says......"GMs ac system is a POS."

 

BTW, Id sell the truck before i let a dealer touch it. Once I take it off the lot

they will never see it again.

 

99.999% of the time, they come back worse, or worse yet,

with all kinds of damage/stains etc. If I cant fix it, it doesnt get fixed.

 

I like to listen to others dealer service horror stories though.

 

I know one guy whos more or less had his whole AC system replaced.

Same thing........NO A/C when the truck decides not to turn on the Pump.

 

I wouldnt mind a 1972 AC system. Those worked when you turn the AC on.

 

Someone has to have a fix.

 

No other vehicles Ive ever had had problems with 'Icing"

 

I mean, everything else can run the AC at -20* if you want, or during a 100* humidity rain storm or whenever.

 

The dealers are aware.......yet. have no answers.

[dewfpo]

Sounds like your compressor is disengaging becasue of a high (compressor) temp or a high pressure situation.

 

You need to get a schematic of the wiring on the A/C system and see if it goes thru a high temp or high pressure switch to protect the compressor.

 

Either that or a temp sensor within the auto climate control (plenum) if flaking out on you.

 

Hard wiring the compressor will cause problems, expensive problems especially at highway speeds on very hot days. (the old systems had expansion valves, in general, these new cycling systems use orifice tubes)

 

DEWFPO

[dewfpo]

Come to think about it, it could also be the compressor relay in the electrical center in the engine compartment. If you can't find a common thread of when it's happening, sometimes a bad relay will cause intermittent contact problems.

 

DEWFPO

[BIGASSZ71]

Take the connector off the low-pressure switch and bend a paper-clip to fit both holes and leave the clip stuck in the end of the connector (not plugging it back up) and see if it will stay on by jumping out the low-pressure switch... worked for me in my Z, couldn't hurt to try.

[Mattt]

Ive had a similar problem coming home from the river on I-10 W. AC worked great for the first 100 miles, then I progressively felt less and less air coming out of the vents, even with the fan set on 5. I think it was icing up as others mentioned. Stopped to eat and it worked good again when we took off. Any way to keep it from icing up?

 

Something else I noticed that's related, my truck seems to drip water forever after I turn it off. The other day I came out of work after not starting the truck for 7 hours, and it was still dripping water up near the RF wheel. There was a spot on the ground and it was coming from the drain hose below the dryer. Should it be taking that long to drain?

 

Im starting to wonder if Ive got an obstruction in the drain or pan and thats why it freezes up after long usage, because the condensation isnt draining quick enough. I checked the end in the engine compartment, and there is no obstruction there. Any way to get into where that drain comes from?

[dewfpo]

This definitely sounds like ICING up. You will need to check your low pressure switch. The one that cycles the compressor. The switch is supposed to control the pressures on the low side so that the evaporator DOES NOT create ice. It will condense allot of water in a humid climate but it should not be so cold as to form ice on the evaporator.

 

DEWFPO

[Mattt]

How can you tell if the low pressure switch is working?

 

As for it being humid....Im talking Mojave desert, so its usually not high humidity.

[dewfpo]

Hook up a low side pressure gauge (~$20 at Wal-Mart) and turn the A/C on. The pressure gauge should be cycling between ~25 psi and 45 psi. The compressor should come on with any pressure above 25 psi. Once the low side pressure reaches 25 psi, the compressor wll cycle off until the pressure comes back up to 45 psi then the compressor should cycle back on, and contimue to repeat the cycle ad nauseum.

 

You can also check your static pressure. Engine off, engine cold.... at 75F the pressure in the low side should be ~70 psi.

 

DEWFPO

[F_L]

I am having the same problem with my 2000 Silverado. The A/C worked great until this summer. Same problem with the compressor cycling off and not kicking back in until it's pretty hot inside. The problem is intermitent and I can't duplicate it at idle. I replaced the pressure switch on the accumulator, no change. Icing up may be a possibility. I'll pull over and check under the hood next time.

If anyone has any other ideas, I sure need a fix for this.