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Discussion Starter · #1 ·
After 32k miles, I had my first failure last week and I wanted to know if anyone else out there has seen the same issue.

On 4/9, I preconditioned the car for 10 minutes and she was nice and toasty (I’m in MI and it was 30F). Upon driving the car, I noticed the cabin getting chillier. I discovered the fan was blowing cold air. I assumed it was a firmware glitch and that the car would "reboot" itself and all would be normal once the car sat for the night. No such luck......so I took it to my local Chevy dealer on 4/13 and they looked it over. It took them all day to download and flash the car’s OS. There were also two recalls that were also uploaded to the car. After all,of that, they concluded it was NOT a software/firmware issue and that the heater may have crapped out. The service gal suggested that the coolant flow may be blocked......I smirked. I’ll be taking it back to the dealer on Monday for them to continue the repairs.

Has anyone else seen this? If so, what was the fix?

Dayle
 

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The service gal suggested that the coolant flow may be blocked......I smirked.
IIRC, the heating system for the cabin does transfer heat via a coolant loop. I'm not 100%, but I thought there was a resistive element embedded in coolant that is then circulated to a radiator of some sort that air blows over, carrying the heat into the cabin.

If the coolant wasn't flowing, that would explain why you weren't getting heat.
 

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I saw a used heater core for sale on ebay for a Bolt it looked like a regular everyday core, except the top tank had a round section where the heating element was.

If you are not familiar with heater cores the typical cores are about 10 inches wide 15 inches long 2 or 3 inches thick (think mini radiator).

The core had a round area built into the main tank on the end where the hoses run out, I don't remember what kind of electrical connector was on it.

What happens with this heater is you apply power the coil in the tank heats as coolant passes by it.

Before I saw the heater core for the bolt, I had wondered if they used a heater much like a portable home heater where air blows over a hot coil but this one heats coolant not just air.

Back when I was 15 I remember being in a 53 Oldsmobile that had an electric heater this was the type that only heated air.

It was a wonderful heater you had almost instant heat but the downfall was that batteries of the day coupled with cars using an old fashion generator couldn't keep up with demand.

You had to put in time watching the amp gauge return to the center point, with everything electric turned off NO HEAT, so your battery had a good chance of starting your car the next time you got in it or you were stuck hoping someone would be kind enough to jump start your car.
 

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Discussion Starter · #5 ·
All nice info....but since this is under warranty, I wasn't going to wrestle with this myself. I took it to the dealer when the part arrived and they installed it yesterday. All appears to be correct. The take away is to take the car to a dealership that is trained in Bolts. This one wasn't and they dropped the ball a couple of times. Lesson learned.

Dayle
 

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Hmmm interesting because my car does that too however I realized it is because the cabin temperature goes beyond what it was before so the air conditioning kicks in to cool it off and bring it to the desire number...
 

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Always wondered why the Bolt and early Leaf used resistive > liquid > air heating. You get instant heat going straight from resistive to air, just like a small space heater. Seems less complicated that way, and there would be slightly less wasted heat since there is no reservoir of warm coolant left over when you turn off the car.
 

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Always wondered why the Bolt and early Leaf used resistive > liquid > air heating. You get instant heat going straight from resistive to air, just like a small space heater. Seems less complicated that way, and there would be slightly less wasted heat since there is no reservoir of warm coolant left over when you turn off the car.
Yup, seemed pretty odd to me too. My guess is something to do with fire hazard. A glowing orange heating element inside a car with synthetic materials all over the interior might frighten the lawyers.
 

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I've had a similar experience. Pre conditioning is requiring increasingly higher temp settings for cabin comfort, 72 has become 84.
Now, cabin does not cool as temp is reduced. At 65, Heater still blows hot air.
Currently at dealer.
 

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Yup, seemed pretty odd to me too. My guess is something to do with fire hazard. A glowing orange heating element inside a car with synthetic materials all over the interior might frighten the lawyers.
I was thinking that too, but electric/air heaters are common in wall heaters in homes. It could be made at least as safe as that, right? Then there is the issue of what happens if there was a fluid leak and the heating element has nothing to dump the heat into? Might even be more dangerous.

Is the heater tied to any other cooling loop? I thought I had read it was, and that would make sense to use waste heat to supplement the electric heater.
 

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Then there is the issue of what happens if there was a fluid leak and the heating element has nothing to dump the heat into? Might even be more dangerous.

Is the heater tied to any other cooling loop? I thought I had read it was, and that would make sense to use waste heat to supplement the electric heater.
The system has a "low coolant" sensor. I recall somebody getting such a screen warning.

Pulling waste heat from the power electronics loop would seem to make sense. But I don't think there is such a heat exchanger in the system.
 

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Follow UP to service appointment... Service advisor misunderstood problem. Heater issue will not addressed until Monday.
As an aside, it's disheartening that service advisors seem to have nothing more than superficial knowledge of Bolt inner workings. When presenting with a problem, I get glazed eyes and a vaccous smile.
 

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Follow UP to service appointment... Service advisor misunderstood problem. Heater issue will not addressed until Monday.
As an aside, it's disheartening that service advisors seem to have nothing more than superficial knowledge of Bolt inner workings. When presenting with a problem, I get glazed eyes and a vaccous smile.
Bummer. I wonder how there was confusion though if the service gal said it might be a blocked line and that the heater may have crapped out? What did they think you brought the car in for?

I've been in the IT service industry for a while now, and I find it extremely useful to repeat back in my own words a summary of the issue the customer is having. This gives them the chance to correct anything I might be misunderstanding.
 

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...I find it extremely useful to repeat back in my own words a summary of the issue the customer is having. This gives them the chance to correct anything I might be misunderstanding.
This is a fundamental principle for accuracy in critical communications. It's why aircraft and train operating procedures require a readback of all clearances.

If you have any doubts about how accurately your service advisor understood your issue, there's no reason why you can't ask him to read back the repair order to make sure he got it right.
 

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Service Follow Up: After several attempts, the technician fixed neither the cabin heater nor the other write ups. The dealership is large, but has only one designated Volt/Bolt tech.
The dealership/technician will not be given another opportunity to fail. Fortunately, there are several other dealerships in the area.
My suggestion when bringing your Bolt for service, is to inquire as to how many Bolt technicians the dealership employs and their level of experience.
 

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I had posted earlier about my non-working heater in my Bolt which was bad from the factory. I haven't updated because since I live in warm SoCal and have been so busy I have yet to bring back to the dealer as I haven't even needed to use it. I'll be bringing it in over the next few weeks as my daughter returns from college and I'll have someone with some time on their hands to help pick me up. All else with the car has been great though.
 

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TSB 17-NA-049 for this. Dealer S/A's are sometimes useless. They can't pay attention and the techs sometimes are worse.

They shouldn't be called Techs.....LOL!

These systems are all monitored and they should be able to pull up DTC's.
Read the TSB I posted and you'll see there are two HVAC DTC's to look for
when a Bolt has HVAC issue's. Granted, it could be something else, but at
least run a vehicle wide DTC check and a bulletin search before wasting time.
 

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Always wondered why the Bolt and early Leaf used resistive > liquid > air heating. You get instant heat going straight from resistive to air, just like a small space heater. Seems less complicated that way, and there would be slightly less wasted heat since there is no reservoir of warm coolant left over when you turn off the car.
This wouldn't apply to the Leaf but for the Bolt you could use the same resistive heater to heat coolant for the cabin or the battery, meaning you'd need only one heater element for both.
 

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IIRC, the heating system for the cabin does transfer heat via a coolant loop. I'm not 100%, but I thought there was a resistive element embedded in coolant that is then circulated to a radiator of some sort that air blows over, carrying the heat into the cabin.

If the coolant wasn't flowing, that would explain why you weren't getting heat.
There's a little on/off pump that circulates the HVAC heater core coolant out to the high voltage coolant heater underhood and back. For this kind of issue, maybe the pump's stopped working? (Not to be confused with the separate coolant circuit and components for the traction battery's pump and lower power HV heater).
 
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