HVAC LED's go dark

[pcguy]

Has anyone else experienced their HVAC LED indicators going dark. Every time I stop in at the dealer, even once when it was doing it and I left it running, by the time the SA comes out, it clears itself. When I say dark, I mean not on at all, and not dim like when the headlights are on.

The LED's I'm referring to are those on the outer edge of the three knobs that show what settings are selected and those for the rear window def. and the seat warmer.

SA says he has no info in the database.

TIA, Nick

 

[DvlsAdv0c8]

Just wondering if you found a solution to this, or if it even happened again?

My BRAND NEW 2015 RS has done this to me three times (it's still under 2000 miles - I've only had it since the beginning of March 2015). The fan control still functions when it happens, but only blows hot air, regardless of the temp setting - no A/C, and no little orange lights on any of the HVAC controls.

It seems mine is heat related - it's happened at the same time of day each time (5:00 PM) when leaving work, all on very warm days (80+).

The first time it happened my car also initially didn't want to start, and once it did, it kept trying to stall for about half of my 6-mile drive home. Not again since, though the car seemed to run a bit sluggish these last two times.

The first time it happened, I thought it might be a fuse issue, because after I got home I messed with the fuse, (didn't actually remove it, don't happen to have a fuse puller right now, just jiggled it a bit) and then it worked. Now I think it just happened to cool off in the amount of time it took to do that.

I did try shutting the car off about half way home this last time and letting it sit for a minute, but it didn't work until after I was home. I guess it needed to cool down more...?

The MyLink display when first starting up on the days of these events shows the ambient temperature on all warm days at right around 100 degrees, even though the actual temp is probably 85-ish. I always noticed this temp discrepancy (probably a result of sitting in direct sunlight for 4 hours a day) in my 2012 LT as well, but never had this HVAC problem in that one.

It has done it now two days in a row, beginning ONE DAY after being at the dealer for recall work, during which time I had them check for codes because my OnStar popped an alert on my Stabilitrak system (no actual problems or codes, of course).

The service guy said the OnStar thing was a result of 'radio interference,' and they also discovered that my tire pressure monitors were alerting as a result of the same 'radio interference' - although strangely, this was not mentioned on the invoice (and I never told them about the two times my tpm light blinked at me on the dash unnecessarily), just that no problems were found. Probably not related to the HVAC issue, though.

Very frustrating considering it's a brand new car with hardly any miles on it. I dread getting the "can't replicate problem" response from the dealer.

 

[Stew]

You both should have heated seats, do the heated seats work when this happens? It's a long shot but I did find this which may be related since it has to do with loss of communication to the HVAC module.

Inoperative Heated Seats

 

[DvlsAdv0c8]

Interesting...I may need to investigate that further. I guess I didn't think to check if the heated seats work when it's already so hot, but I will check. Thanks for the link - more ammo for my arsenal. I am determined to figure this out, because I want to give GM as much info as possible when I pull into the bay and my car looks fine to them.

It happened again today. I've been running an experiment of sorts. Every time this has happened, my car has been parked between two tall, brick buildings on an E/W running street, with the front of the car facing west, in direct sunlight all afternoon after 2:00 on very warm, sunny days.

So, last week I made a point of parking so the front of the car was not in direct sunlight or the whole car was completely shaded in almost identical conditions. No problems. Not one, on any of those 4 days.

Today I parked back in my regular spot, facing west in full sunlight. Sure enough, it happened again. But the lights and A/C didn't quit working until after I was about 1/4 of the way home. And my ambient temp read 100 degrees when I first got in the car.

I turned off the key at a stoplight, restarted the car, and the HVAC control lights came back on - only to go right back off when I turned on the AC and cranked the fan.

About a 1/4 mile from home, my fuel gauge (full tank, btw) display cycled down to zero and the mileage number went flat - just dashes. The fuel gauge cycled back up to full, the mileage number returned, and the HVAC lights came back on. But it would only blow hot air, and the lights went right back off again.

Once I was home, I left the car running to see what would happen. I sat and watched over the next 15 minutes as the fuel gauge display and mileage reading disappeared and returned, and the HVAC control lights came on and went back off. It seems to cycle quickly, and each time the lights came back on I could hear what I am guessing is the AC compressor start running at about the same time. When the lights go out, it gets quiet. I tried to take video of it, but my phone is crap.

I checked all the HVAC and AC Clutch fuses - fine. But, when the HVAC control lights come back on, the engine (or compressor?) gets louder, and it sounds like any and all fans are running. And the engine compartment is REALLY HOT.

I'm still convinced this is temperature or humidity related somehow, just not sure what's being affected. And as the clouds moved in and the sun went away, I restarted the car and all was well. Go figure. Next time I'm driving straight to a Chevy dealer.

I have yet to hook up a scanner while it's happening. I now have a scanner with me and will hook up next time it happens - on my way to the dealership.

 

[pcguy]

Happens off and on and continues today. Have heated seats, and can't say if they work or not when it happens, but the HVAC all seems to work - you just can't see what's what....

Thanks for the link - I'll pass that on to the SA.

Nick

 

[Luv2xlr8]

I've had this happen to me a couple times before but not anymore. I drive a LS model so no heated seats here.

 

[Chevrolet Customer Care]

Interesting...I may need to investigate that further. I guess I didn't think to check if the heated seats work when it's already so hot, but I will check. Thanks for the link - more ammo for my arsenal. I am determined to figure this out, because I want to give GM as much info as possible when I pull into the bay and my car looks fine to them.

It happened again today. I've been running an experiment of sorts. Every time this has happened, my car has been parked between two tall, brick buildings on an E/W running street, with the front of the car facing west, in direct sunlight all afternoon after 2:00 on very warm, sunny days.

So, last week I made a point of parking so the front of the car was not in direct sunlight or the whole car was completely shaded in almost identical conditions. No problems. Not one, on any of those 4 days.

Today I parked back in my regular spot, facing west in full sunlight. Sure enough, it happened again. But the lights and A/C didn't quit working until after I was about 1/4 of the way home. And my ambient temp read 100 degrees when I first got in the car.

I turned off the key at a stoplight, restarted the car, and the HVAC control lights came back on - only to go right back off when I turned on the AC and cranked the fan.

About a 1/4 mile from home, my fuel gauge (full tank, btw) display cycled down to zero and the mileage number went flat - just dashes. The fuel gauge cycled back up to full, the mileage number returned, and the HVAC lights came back on. But it would only blow hot air, and the lights went right back off again.

Once I was home, I left the car running to see what would happen. I sat and watched over the next 15 minutes as the fuel gauge display and mileage reading disappeared and returned, and the HVAC control lights came on and went back off. It seems to cycle quickly, and each time the lights came back on I could hear what I am guessing is the AC compressor start running at about the same time. When the lights go out, it gets quiet. I tried to take video of it, but my phone is crap.

I checked all the HVAC and AC Clutch fuses - fine. But, when the HVAC control lights come back on, the engine (or compressor?) gets louder, and it sounds like any and all fans are running. And the engine compartment is REALLY HOT.

I'm still convinced this is temperature or humidity related somehow, just not sure what's being affected. And as the clouds moved in and the sun went away, I restarted the car and all was well. Go figure. Next time I'm driving straight to a Chevy dealer.

I have yet to hook up a scanner while it's happening. I now have a scanner with me and will hook up next time it happens - on my way to the dealership.

Hi DvlsAdv0c8,

We would be happy to add any additional assistance with this as well! Feel free to shoot us a private message over if you need us to look into this further when you decide to bring this to your dealership's attention. We look forward to hearing from you soon with any updates!

Patsy G
Chevrolet Customer Care

 

[DvlsAdv0c8]

Thanks again, Patsy, for contacting me. Here's where it stands as of today...

It was hot enough today for it to happen again...only it waited until I was almost home.

I pulled into a parking lot and plugged in the code reader and...ZERO CODES. I even unplugged it and plugged it back in - still no code.

So I headed for the dealership, about 5 or 6 miles away, watching the whole thing cycle through about 4 or 5 times. I also noticed this time that either when the HVAC control lights go off (or was it come back on? Not sure...) my Stabilitrack and TPM lights flash briefly on my instrument panel.

(Funny how OnStar alerted to a potential problem with my Stabilitrack that was never found, and the service guys found the radio interference thing with my TPM system...related somehow after all maybe?)

So, as soon as I got to the dealership, I left the car running and got the attention of the first service writer I saw. He came out to the car while I explained the issue, got in the car, and watched it cycle through at least once, if not twice. HE SAW IT HAPPEN.

He felt the air from the vents go from cool to hot, saw the gauges freak out, and saw the HVAC control lights go off and on. Oh, yeah, we also watched my tach jump a little each time, which I hadn't noticed before.

He then went in and wrote a short novel about the problem and what he saw. It was very gratifying to see him try his best to detail everything. He said he's never seen anything like it.

(One of the other service guys started reading over his shoulder while he was typing, because he was so intensely focused trying to get in all the details - he also said he's never seen anything that weird before.)

So HOPEFULLY they will figure it out. In the meantime, I get to test drive a 2015 Buick Regal Turbo loaner car.

FINGERS CROSSED...

 

[Chevrolet Customer Care]

Thanks again, Patsy, for contacting me. Here's where it stands as of today...

It was hot enough today for it to happen again...only it waited until I was almost home.

I pulled into a parking lot and plugged in the code reader and...ZERO CODES. I even unplugged it and plugged it back in - still no code.

So I headed for the dealership, about 5 or 6 miles away, watching the whole thing cycle through about 4 or 5 times. I also noticed this time that either when the HVAC control lights go off (or was it come back on? Not sure...) my Stabilitrack and TPM lights flash briefly on my instrument panel.

(Funny how OnStar alerted to a potential problem with my Stabilitrack that was never found, and the service guys found the radio interference thing with my TPM system...related somehow after all maybe?)

So, as soon as I got to the dealership, I left the car running and got the attention of the first service writer I saw. He came out to the car while I explained the issue, got in the car, and watched it cycle through at least once, if not twice. HE SAW IT HAPPEN.

He felt the air from the vents go from cool to hot, saw the gauges freak out, and saw the HVAC control lights go off and on. Oh, yeah, we also watched my tach jump a little each time, which I hadn't noticed before.

He then went in and wrote a short novel about the problem and what he saw. It was very gratifying to see him try his best to detail everything. He said he's never seen anything like it.

(One of the other service guys started reading over his shoulder while he was typing, because he was so intensely focused trying to get in all the details - he also said he's never seen anything that weird before.)

So HOPEFULLY they will figure it out. In the meantime, I get to test drive a 2015 Buick Regal Turbo loaner car.

FINGERS CROSSED...

Not a problem! My fingers are crossed for you as well! I'm happy to hear the dealership has been actively looking into this further for you. I do look forward to the outcome soon!

Patsy G
Chevrolet Customer Care

 

[DvlsAdv0c8]

Well, so much for that, at least for now.

It just figures that I get the car to the dealership at the beginning of a holiday weekend, not to mention the only two days they actually did anything with it have not had the right conditions for it to happen again.

And I know that even though I was very thorough about describing the conditions that it always happens in, the ways they told me they tried to replicate it were both very weak attempts even under ideal conditions. (Yes, I know my car is not the only one in the shop.)

So I'm picking up my as-of-yet undiagnosed and unrepaired car that I can't even try to fix myself without voiding the warranty, and driving a broken car until I figure out what to do next. I knew this would happen.

I can always drive straight to the dealership again the next time it happens and hope for the best, I suppose. I'm really disappointed. I don't know if there's a safety hazard involved or not. I don't like it. I also don't like not knowing if I'll have A/C on a 90 degree day.

Any ideas, Patsy G?

 

[Stew]

I wonder if it would be helpful to the tech if you were able to grab your cell phone and take a video of it next time it happens. I know the service writer saw it and documented it but like they say - a picture, I mean video, is worth a thousand something or other.

 

[Chevrolet Customer Care]

Well, so much for that, at least for now.

It just figures that I get the car to the dealership at the beginning of a holiday weekend, not to mention the only two days they actually did anything with it have not had the right conditions for it to happen again.

And I know that even though I was very thorough about describing the conditions that it always happens in, the ways they told me they tried to replicate it were both very weak attempts even under ideal conditions. (Yes, I know my car is not the only one in the shop.)

So I'm picking up my as-of-yet undiagnosed and unrepaired car that I can't even try to fix myself without voiding the warranty, and driving a broken car until I figure out what to do next. I knew this would happen.

I can always drive straight to the dealership again the next time it happens and hope for the best, I suppose. I'm really disappointed. I don't know if there's a safety hazard involved or not. I don't like it. I also don't like not knowing if I'll have A/C on a 90 degree day.

Any ideas, Patsy G?

Hey there,

Very sorry for this outcome! I can definitely understand how frustrating this may seem for you, and I would be more than happy to reach out to the dealership on your behalf or if you prefer for me to locate another dealership in your area for a second opinion, I can do that as well! Just send me a private message .

Patsy G
Chevrolet Customer Care

 

[pcguy]

No easy answer on this one

I've had this problem since my 2012 was new and if you can't readily replicate, no one can fix it. Been to the dealer with the problem (similar - see original post #1) with the led indicator lights dark (not working) and the engine running. Just as soon as the ignition is turned off and back on, the problem is gone and only reappears randomly.

If anyone finds a fix for this, I'd like to know about it.