[MikeZ]

OK, just to get this out of the way - Auto Defog is turned OFF. Besides that, it's currently clear and very low humidity.

What's happening is that no matter how warm we set the desired temperature in our 2014 Volt, the Air Conditioning Indicator on the Climate Screen will almost always go to "ON" when ECO or Comfort is selected. When doing this, the air blows cold. Very cold - I believe the AC is on. Sometimes if I'm messing with temperature or turning on Defrost, both the the Air Conditioning Indicator AND the Heat Status Indicator will go to "ON" - but only momentarily. Then it will revert back to AC only.

Something that is probably related - the Outside Air Temperature Display seems to always be displaying 38 degrees, even in our garage that is probably in the mid 50s. That alone shouldn't make it always go to AC, however. I'm suspecting that both the outside and cabin temperature readings are messed up somehow, and confusing the system. Is there a common point of failure that could do this?

Any suggestions or insights? We'll probably take it to the dealer, but I've always found things go better if we already know the root cause.

Thanks,
Mike

 

[VoltenRock]

Is the auto-defog ON? On my old 2013 (and now 2017), A/C switches on if there is a certain amount of humidity inside the cabin to keep the windows clear. This is independent of temperature--the A/C is just there really to keep the windshield clear not to cool the cabin.

The only way to have no A/C is to not use eco or comfort and just fan only with the Auto-Defog set to OFF. Then you have to use the waste heat from the ICE for the cabin.

I've noticed that my Gen 2 fogs up REAL easily so I end up just dealing with the A/C + heat most of the time.

 

[freshcut]

My '13 does the same thing. I have auto-defog turned off as I read that will prevent the a/c system from activating, but it didn't seem to help. I've just come to accept that heat will always include a/c use. As for the abnormal temp reading, The sensor is inside the front passenger side wheel well and shouldn't impact the cabin temperature setting. It may have failed.

On a side note, there have been several posts related to non-operational heat in EV and ICE mode (usually one, rarely both). In EV mode, it's typically the coolant heater. I had an issue with mine where the coolant valve was stuck for EV mode, so I only got heat until the engine started to operate. After that, the a/c would make the cabin incredibly cold. Might be similar to your situation, but reversed (heat in ICE mode).

 

[Foose]

No clue what's going on, seems as though it's not reading temps and thinks its blowing warm air. Volt's seem to be a little wonky when it comes to climate control. When I first got mine it wouldn't blow hot air no matter what I tried. Then one day it just started working perfectly and has been for the last year. Now, some times it will blow just above room temp when it's set to HI, but if I turn it down to 88 it will blow plenty of hot air. It doesn't always do that tho. This thing just has quirks, I deal with it.

Any time you turn the defrost on the AC will kick on, by design. It's meant to pull moisture out of the air, thus defogging the windshield. You can not have the defrost on without the AC being on.

 

[MikeZ]

Is the auto-defog ON? On my old 2013 (and now 2017), A/C switches on if there is a certain amount of humidity inside the cabin to keep the windows clear. This is independent of temperature--the A/C is just there really to keep the windshield clear not to cool the cabin.

The only way to have no A/C is to not use eco or comfort and just fan only with the Auto-Defog set to OFF. Then you have to use the waste heat from the ICE for the cabin.

I've noticed that my Gen 2 fogs up REAL easily so I end up just dealing with the A/C + heat most of the time.

Let me reiterate (see my first line above), AUTO_DEFOG IS OFF. And I'm not concerned that AC comes on periodically, it's that AC comes on, stays on, and blows cold air. Continuously - it does not turn off, the heat does not go on (except maybe momentarily). If we get in the car with a cabin temperature of 60F, we're going to be at 55F shortly. This has nothing to do with humidity. This has to do with AC only, no heating.

BTW, I've had this car for 5 years. This behavior is new within the past week. I know something is wrong - just hoping someone might be able to point me to the cause...

 

[MikeZ]

I had an issue with mine where the coolant valve was stuck for EV mode, so I only got heat until the engine started to operate. After that, the a/c would make the cabin incredibly cold. Might be similar to your situation, but reversed (heat in ICE mode).

I suspect it's some kind of mechanical fault, the thing is that the Heat Status Indicator doesn't even show as on. I'm guessing the car is confused as to what the temperature is. I guess it's just time to take it in and trust to the dealerships diagnostic capabilities.

 

[MikeZ]

No clue what's going on, seems as though it's not reading temps and thinks its blowing warm air. Volt's seem to be a little wonky when it comes to climate control. When I first got mine it wouldn't blow hot air no matter what I tried. Then one day it just started working perfectly and has been for the last year. Now, some times it will blow just above room temp when it's set to HI, but if I turn it down to 88 it will blow plenty of hot air. It doesn't always do that tho. This thing just has quirks, I deal with it.

We've had the car 5 years, and our climate control has been great - until now. I'm guessing it's intentionally blowing cold air (the Heat Status Indicator is off, AC is on continuously, auto-defog is off, and the air is bone dry).

I guess we'll just take it in...

 

[jcanoe]

You might try pulling some fuses, seeing if the HVAC system will reset.

 

[Foose]

The AC being on isn't necessarily the problem. When you turn on the defrost it blows hot with the AC on (or at least it should!), so the AC being on doesn't mean anything, other than it's circulating hot air through the drier to remove moisture. I doesn't hurt anything to run your AC with the heat on, other than a little fuel/battery economy and a tiny bit of wear and tear.

I would say your blend doors are the problem, but I don't know if Volts even have those (it's literally a "door" or valve in the HVAC system, usually buried deep in the dash, that opens to allow hot air through (or the other way around)).

Check all of your coolant levels before you take it in, if you haven't. In conventional vehicles, if the coolant level is low there isn't enough coolant to circulate through the heater core so it blows cold, usually at a stop but works in motion.

 

[MikeZ]

You might try pulling some fuses, seeing if the HVAC system will reset.

Good idea - I'll give it a try once my daughter gets home with the car. Thanks...

 

[MikeZ]

The AC being on isn't necessarily the problem. When you turn on the defrost it blows hot with the AC on (or at least it should!), so the AC being on doesn't mean anything, other than it's circulating hot air through the drier to remove moisture. I doesn't hurt anything to run your AC with the heat on, other than a little fuel/battery economy and a tiny bit of wear and tear.

I would say your blend doors are the problem, but I don't know if Volts even have those (it's literally a "door" or valve in the HVAC system, usually buried deep in the dash, that opens to allow hot air through (or the other way around)).

Check all of your coolant levels before you take it in, if you haven't. In conventional vehicles, if the coolant level is low there isn't enough coolant to circulate through the heater core so it blows cold, usually at a stop but works in motion.

I kind of doubt it's any of those. If the Heat Status Indicator is telling the truth, the heating system isn't even turning on. AC on, Heat off...

 

[VoltenRock]

Let me reiterate (see my first line above), AUTO_DEFOG IS OFF.

Ok, man. Missed it.

 

[obermd]

The fact that the external temperature is way off makes me think the external temperature sensor has failed. When this sensor fails the car will do strange things like run the blower in defrost mode.

 

[freshcut]

As I recall with mine, it would indicate heat for a few minutes initially, but then rarely show heat activity again. I suspect it was doing so just long enough to make the coolant hot, but since it wasn't circulating through the core as intended, it would turn the heater off since the coolant was sufficiently "hot" according to the sensors and only intermittently reactivate the heater to maintain the coolant temp.

On a side note, do you get heat when running in hold mode or when the battery is depleted? It really may just be as simple as a failed or stuck 3 way valve.

 

[hickman55]

If you have a OBD2 tool, check to see if there is any draw on the 12 volt battery when off. I had a car with a stuck A/C relay and the way we found out was it drained the battery if it sat idle for more than a day or two. The A/C compressor was always engaged, even with the climate controls off.

 

[16falcon]

I had the same issue this year. No heat in EV or ICE modes, AC on instead. I think the heat indicator on the climate control screen is only indicating electric heat, not ICE generated heat. It would come on for a few seconds now and then but system continued to blow cold air. Dealer replaced a valve and that helped but still not much heat. They determined that the heater core was bad (clogged?) and replaced that. Worked great again now. Glad I bought the extended warranty, it was covered.