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Discussion Starter · #1 ·
Had the 2nd, "permanent" battery recall service on my 2017 Bolt a week and a half ago. Too soon to tell for sure but sure seems to me automatic temperature control is working a LOT better.

Poor auto temp control is the only serious complaint I've had about the Bolt. Get in the car when outside temp was 80+ and inside was hotter. Set temp to 77. Fan barely came on and what little air came out of upper vents was outside hot. (I never actually checked with thermometer but it surely wasn't cool.) Bump the temp down one degree at a time. Nothing changed much until it reached 72. Then fan switched up to high speed and frigid air blasted out of upper vents. Conversely when outside air 50. Set temp to 65. Fan barely on and air out of vents felt outside cold. Nothing much happened as temp bumped up from 65 to 70-something when fan suddenly switched to high and hot air blasted out of upper vents. I figured it was designed that way to reduce temp control impact on range. I don't drive long enough at one time to care a lot and just lived with it.

After recall service and software update last week, outside temp was 85+. I noticed right away when I set the temp to 77 deg, the fan moved up to mid-range and cool-but-not-frigid air came out of vents immediately. As I bumped temp down, the car actually appeared to be listening: Fan went faster and air out of vents got cooler but just proportionally to temp setting. Bumped back up and fan slowed down and air got less cool but not hot. I haven't driven far enough since the update to see if cabin temp stabilizes at set temp and won't be able to try heating for a few months but I'm newly optimistic. I didn't complain to dealer about temp control and the service ticket doesn't mention doing anything but the software update so I'm wondering if GM did something wonderful to the software. Have the rest of you noticed an improvement?
 

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2021 Bolt LT
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I noticed that for the first time in my 2021. I never had to use the AC much until the other day when it was 104 out. I got into the Bolt and it was really hot. I turned on the AC and set it to like 74. the fan came on and was blowing full for like 5 mins and never got cool. I adjusted it until it said low. still no cool air for another 10 mins, about half way home on the freeway. it started to get cool. not as cold as I am used to in my other ICE vehicle, after my 32 mile commute home it was cold by the time I drove into my Driveway. I know it had to work on removing the heat saturation from the inside, but I feel like it should have done it faster than it did. the next day no issues, but it was not that hot. Maybe it was also working on chilling the battery as well at the same time. I will continue to monitor it on my next really hot day.
 

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That was my one complaint about my 2019. 74 was the cutoff in that car. If I set it to 75 and it was 85 in the garage, it'd literally blow HEAT for several miles until it switched to AC. The center display would actually display it was calling for heat. Switch it down a couple degrees to 73 and it'd switch from heat to AC. It's definitely the worst HVAC system I've ever experienced. Eventually I opted to leave it set to 73. While that was a bit too cold for me, if I set it to 75, it'd blow heat in the summer at temps up to about 87F outside.

If the recall did change something about that scenario, it'd definitely be a good thing!

Mike
 

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My first inconvenient fix for the 2017 Bolt's stupid AC/heater that blasts warm air in moderate temps and sucks many kWh while in the process of making one uncomfortable (and providing for conversation talking points -- is the heat on for some reason?) I removed two fuses under the hood for the high voltage DC immersion heater (fuse 60, 5 amp) and for the heater pump for the interior coolant/heater loop (fuse 65 10 amp). Torque Pro still shows 7.5 kwh but that is the 'ask' not what is delivered with the fuse removed. I jerry-rigged a switch last winter as I actually DID want heat & defrost sometimes. And wanted the heater to not heat unless the pump was running to avoid boiling the coolant.

But: I yanked it all out when the battery fire recall became far more important and I figured it would just be too much for the dealer to think about.

Summary: remove fuse 60 for the heater. Torque Pro will still show 7.5 kW. The coolant pump may run off and on, circulating what it imagines might be the expected hot water. Then remove fuse 65 for the pump. Then all is good. In my mild San DIego world, I leave both fuses out for months spring-to-winter, and have nothing but cold AC. I've only noted one warning about 'Check service heater circuit' or some such nonsense.

I used two 'add-a-circuit' Micro-2 connectors and an SPST switch to jumper fuses 60 an 65. There is just barely enough space to get them into the fuse block. Me? I like the simplicity of just taking fuses out and putting them back when I actually want heat.
 

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2021 Bolt LT
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312 Posts
I am experiencing the same with my 2021.

I normally leave it on 75 as it is the most comfortable temp and it does not steal much power. That only works in the afternoon on my way home though. Leaving it at 75 means that the heater is on when I start my drive in the morning. I end up turning it down to 73 and it switches to cool, then switch it back up to 75 and it then stays on cool. It is quite annoying.
 

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2020 Chevrolet Bolt
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5,736 Posts
The "Auto" HVAC setting in the Bolt can run both the heater and the air conditioner simultaneously, presumably to manage both temperature and humidity simultaneously. However, turning off the "Auto" mode and manually selecting AC or heat will only use what you select. Having said that, I turn "Auto" back on just before I shut off the car, so that preconditioning will work.
 

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Discussion Starter · #7 ·
I appreciate hearing it wasn't just my Bolt's auto temp control that didn't work well. If you've had the latest, "permanent" recall service, do you think it improved temp control or that just my imagination?
 

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2021 Bolt LT
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312 Posts
The "Auto" HVAC setting in the Bolt can run both the heater and the air conditioner simultaneously, presumably to manage both temperature and humidity simultaneously. However, turning off the "Auto" mode and manually selecting AC or heat will only use what you select. Having said that, I turn "Auto" back on just before I shut off the car, so that preconditioning will work.
I trust myself to remember to adjust down and then back up at some point while driving rather than remembering to put it back on auto after I arrive home. I don't have that good of memory unfortunately.
 

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turning off the "Auto" mode and manually selecting AC or heat will only use what you select.
Mostly true, but not 100% true. If the temperature stabilizes enough it thinks that the A/C on low will make it too cool and it will turn on the heat too. I've only noticed this while sitting a while in the shade, but confirmed it is happening with TorquePro. Setting the fan speed manually seems to make it worse, because the only thing it can do is heat or cool. With the fan on auto it will drop the speed to low before resorting to turning on the heat. This is in extremely dry Phoenix with auto-defog off. Changing the temperature setting a degree or two turns it back off so I really think it's a temperature blending effort more than a humidity control effort.
 
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