A/c Issue Related To Starting The Engine

[wdh371phy]

Hi all,

 

I have a 2004 Silverado with a long running issue with the A/C init. Whether the A/C is going to work or not all seems to be determined when I start the truck. If the A/C is working, it works fine. If it isn't, there's no adjustment you can make to get it to work. All you can do is stop the truck, turn off the engine for 20 - 30 seconds, restart it and hope for the best. Usually it will work after a couple tries but it's your only hope. Very much like having to reboot your PC it feels like.

 

I've had it into the Chevy dealer several times for this problem. They replaced the control inits that open the A/C flaps in the dash and the last time they changed out some temp sensor. They did that to try something because they couldn't get the A/C to fail while they had it....lucky me.

 

The biggest problem I have is that the dealership can't seem to sort out the problem....and I've paid in excess of $800 so far on this.

 

Has anyone experienced a similar issue? I don't intend to fix it myself but I'd sure like to be able to point the dealership in the right direction if someone else has experienced a similar issue.

 

Many Thanks for your anticipated Feedback that will help fix the problem!

[wdh371phy]

No one's ever experienced this problem before???? Any suggestions?

 

Thanks in advance for any idea's anyone might have!

[nickvrebel]

well, you haven't given the first symptom other than "it doesn't work"

 

define: "It doesn't work" - does the fan not blow? does the compressor not come on? does everything work like it should but not blow cold?

 

answers to all of those questions would be a start to help diagnose. If anyone suggested an answer other than "bring it to a competent mechanic" it would be nothing but a generalized answer to some possible problem out of many possibilities.

 

if you can not answer those questions, bring it to a competent mechanic.

[wdh371phy]

Sorry....

 

Inside the truck, everything seems normal except it blows hot air whether you have the button for the A/C enabled or not. Speed of the fan changes as you change settings.....blows hot air if you call for heat.

 

I'm going to say the compressor isn't coming on because when it's not working, I never see condensation dripping from underneath after I stop the truck where I do if the A/C had been working properly. I will confirm that the next time it happens.

 

Thanks

[wdh371phy]

Sorry again...

 

Inside the truck, everything seems normal except it blows ambient uncooled air whether you have the button for the A/C enabled or not.

[wdh371phy]

More info... Drove the truck ~15 miles this AM and the A/C worked fine.

 

Got in it 3 hours later....temps ~95F and the A/C wouldn't work. Settings are for the slider all the way to cool, fan on #2 and the A/C button enabled....I generally leave it that way all the time on start up. I've tried having the A/C off when I start and then turning it on....doesn't help. By the time I got home, there was zero condensate dripping from beneath the truck.

 

Started the engine 3 hours later and no A/C. Turned the engine off & on 5 times before the A/C started working. Was able to turn the blower to # 4 and it was working fine. Drove 5 miles and stopped with the engine idling while I got out of the truck for ~ 5 minutes. Got back in and it was blowing ambient (essentially hot air since it was now 100F) air. Tried restarting the engine several time and no go.

 

When I got home, there was zero condensate dripping from beneath the truck.

 

These symtoms must mean something to somebody....please help! To me it means the truck is ready to get pushed over a cliff...except there isn't any here in SC. As far as bringing to a competent mechanic....if the GM dealership don't have them we're all screwed! I've had it in there several times for this same problem.

 

For the most part, the A/C worked more often than not the last couple weeks....totally erratic.....no rhyme nor reason to whether it's going to work or not when you start the truck......except there's a better chance for failure when it's really hot out.

[flhusa1]

have you checked your low pressure cycling switch? if you know where it is try tapping on the switch and see if ac starts to work. gm had a bunch of bad switches. there is a tsb for this. napa has them.

 

switch

 

tsb for no ac

[jro909]

so let me guess this right, you dropped hundreds of dollars at the dealer so payed professionals can cure your problem? and they diden;t fix it so your asking total strangers online to tell you how to fix it?

 

see the what the **** factor here?

[TexasAl]

I'm thinking that flhusa1 has a very plausible cause for this. I was thinking it has to be a temp. sensor or the A/C control unit. I think you can jump some wires at the compressor to force it to start regardless of the signal from the sensor. I'm sure somebody can chime in on how to do this.

[flhusa1]

if he jumps out the low pressure cycling switch and it works that proves it. he cannot run it like this because the coil will ice over. do not ask me how i know. there are plenty of times the so called pros say there is nothing wrong or we cannot get it to do that. they are are not perfect and only know what to do according to their training or the repair procedure.

[flhusa1]

if he jumps out the low pressure cycling switch and it works that proves it. he cannot run it like this because the coil will ice over. do not ask me how i know. there are plenty of times the so called pros say there is nothing wrong or we cannot get it to do that. they are are not perfect and only know what to do according to their training or the repair procedure.

[wdh371phy]

To jro909....You guessed right but I fear it's the world we live in now.. No question, cars today are built better and more reliable but when it comes to some of these sporadic out of the ordinary type problems, even the dealerships appear to fall into the trial and error type mode I'm finding. I'm really not faulting them....just seems to be the reality sometimes. Thankfully there's forums out there these days for about any subject matter one can think of to solicit other peoples opinions and experiences.

 

 

To flhusa1 & TexasAl

Thanks...I'm not a mechanic but I will find out where it is and how to temporaily jump it out. I read the tsb and although that was for a 2003 Silverado, seems to describe the problem to a T. Next time it happens, I'll try tapping it first and if that doesn't work, then I'll jump it out. If it works, I'll have it changed out....or maybe do it myself....looks like it just unscrews.

 

Thanks everyone....at least gives me a direction to go and i'll let you know how it works out.

[flhusa1]

the tsb was released in 2003 so it can only include trucks built up to that date. yours has the low pressure cycling switch. the switch sticks in the off position. when you hit a bump or vibration sometimes unsticks causing your ac to start working. this switch controls the compressor clutch.

[nickvrebel]

I've been away a few days, but it looks like you are getting some info flowing now...

 

don't always assume a dealership mechanic is any better than an independent shop, I've known plenty of "mechanics" that worked at dealerships that were nothing more than parts changers. If you've spent that much and still haven't got this issue fixed it's time to find another shop, preferably one that specializes in a/c.

 

just a guess on what's showing here: swap around some relays in the underhood fuse panel, there are several of the same type in the box, see if the problem goes away or moves somewhere else, past that it sounds like a sensor going out (or the system is over/ under charged)

[abnjeffy]

I had/am having issues with my air. 09 5.3 Sierra crew cab w/ dual zone climate control. The air wouldn't work sometimes. Other times it would randomly start blowing hot air out of one side when it was set to cool. I took it in and no fix, a few months later GM sent out a bulletin, it was a programming issue and they fixed it with a computer reprogram or something. That was the end for about a year...

 

Now things started to get wierd again. It wont blow sometimes when I start the truck or it will cut in and out every one or two seconds. I have noticed that if I HOLD the 'fan up' button down it will blow until I release it. This goes away after about ten minutes and it functions normally. It still once in a blue moon does the thing where one side starts blowing hot air but now it only lasts for a few seconds and rectifies itself. I also noticed it doesn't get as cold as it used to.