Is HVAC burning you up too? Chevy says "nothing wrong"
- Thread starter rybolt
- Start date
Help Support Chevy Bolt EV Forum:
drdiesel1 said:
drdiesel1 you are my freakin' hero. I called Chevrolet Customer Assistance today and had them re-open my case. (As you may recall from the original post, I last left off with them parroting my dealer's utterly preposterous "Vehicle is operating as designed" determination, with them refusing to follow up or even consider the measurements I'd taken.) They have now updated my file and will have someone contact me tomorrow with the next steps.drdiesel1 said:
While I'm not entirely shocked (shocked, I say!) that my local dealer missed this TSB, the fact that the "specialists" (and their manager) at headquarters were utterly incapable of connecting the dots back to such an obvious service bulletin just makes me want to face-palm from the rooftops.
Oh well, hopefully this is the turning point. I'll post as soon as I have something new to report...
oilerlord
Well-known member
rybolt said:
They kept your car for three days but probably spent about three minutes actually "working" on your car. Time to find another dealership.
Sigmasailor
Member
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- Feb 4, 2017
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- 16
Wow, for any dealer to figure this out all by themselves they have to actually be able to read? Amazing!
SeanNelson
Well-known member
I've heard so many complaints about dealers not being able to diagnose "known problems" like this that I kind of wonder if GM's information systems are to blame. It seems to me that a dealer's service department should be able to do a search for symptoms against GM's database of service bulletins to easily find the cause of these problems. The frequency with which the dealers aren't solving these suggests to me that maybe they can't or that perhaps the search engine or the bulletins' keywords aren't up to snuff. Or, heaven forbid, that all they have is a list of TSBs that they have to scroll through looking for something that seems applicable.Sigmasailor said:
SeanNelson said:
Pretty much, if you want as much info as possible. It will narrow down with key words, but it's still a matter of time to search for them.
They don't pay us to research anything. We get 3 tenths of an hour to find out what's going on. That's it!
After speaking to Chevrolet Customer Assistance on Friday, and phoning the dealer Monday afternoon, I finally got a call back today. My dealer's "Customer Experience Manger" said that the tech didn't apply this TSB the first time I took my Bolt in because it was not reporting certain DTCs required by the bulletin. (I wasn't going to argue, but that's a very creative interpretation of the phrase "may find one or more DTCs set".) She also claims that this bulletin calls for both a hardware AND software ("reprogramming") fix. Should I be worried?drdiesel1 said:
In any case, they have agreed to perform the work and I have an appointment tomorrow. I will continue to follow up as things unfold...
As previously posted, I took my Bolt to the dealer yesterday to have them perform TSB 17-NA-049. They informed me that no DTCs were reported, but agreed to perform the TSB anyway. After service, the tech reported finding no damage to the duct temperature sensor wiring. However, the service manager was kind enough to allow me to attempt to demonstrate the "Drunk Temperature" behavior on both my vehicle AND ON ANOTHER BOLT!
At first, and to my chagrin, both vehicles appeared to cooperate, cooling down from their "parked in the sun" temperatures as we tested for the better part of an hour, shaded from direct sunlight under the service department's awning. But being that the dealer folks were so patient with me, I was permitted to run a second trial, before which I powered off both cars and "aired them out" for about 15 minutes with the windows down.
When I powered both cars back on, with the Climate Control again set to 74º "Auto", both cars started warming up inside. Sadly, I only had one temperature logger (I used a portable thermometer on the test car, but neglected to take good "start" and "finish" photos...shame on me!), so below is the graph from my car. Roughly speaking, the test car was about 4 degrees cooler throughout my tests. (It arrived with the climate set all the way "LOW" so I suspect it started out cooler at the beginning of the experiment.)
I would ask anyone who has been following along this far to grab a thermometer and test your Bolt.
Start with your cabin temperature at "air temperature" (not baking in the sun; "air it out" first if it has been) and see what happens over about a 30 minute window at full "Heat & A/C" Auto (push "AUTO" to return all settings to full automatic) with the temperature set to 74º F.
View attachment RYBOLT 05-04-17 Dealer Diag.png
At first, and to my chagrin, both vehicles appeared to cooperate, cooling down from their "parked in the sun" temperatures as we tested for the better part of an hour, shaded from direct sunlight under the service department's awning. But being that the dealer folks were so patient with me, I was permitted to run a second trial, before which I powered off both cars and "aired them out" for about 15 minutes with the windows down.
When I powered both cars back on, with the Climate Control again set to 74º "Auto", both cars started warming up inside. Sadly, I only had one temperature logger (I used a portable thermometer on the test car, but neglected to take good "start" and "finish" photos...shame on me!), so below is the graph from my car. Roughly speaking, the test car was about 4 degrees cooler throughout my tests. (It arrived with the climate set all the way "LOW" so I suspect it started out cooler at the beginning of the experiment.)
I would ask anyone who has been following along this far to grab a thermometer and test your Bolt.
Start with your cabin temperature at "air temperature" (not baking in the sun; "air it out" first if it has been) and see what happens over about a 30 minute window at full "Heat & A/C" Auto (push "AUTO" to return all settings to full automatic) with the temperature set to 74º F.
View attachment RYBOLT 05-04-17 Dealer Diag.png
You might be fooling the auto settings with the car in the shade :idea:
Here's some info on the auto systems.
The AC compressor function is to provide refrigerant flow in the AC refrigerant loop to help cool down the cabin, help dehumidify the air in a defrost mode and help maintain the battery temperature. Rather than a more-typical pulley, the A/C compressor uses a 3-phase alternating current, high voltage electric motor to operate. It has an on-board inverter that takes high voltage direct current from the vehicle's high voltage battery and inverts it to alternating current for the motor. The AC compressor shall be activated when any of the three following events occur:
The customer pushes the AC button or
The HVAC control, in ECO climate or Comfort Climate Settings, requests the electric AC compressor on to help in cooling the cabin or removing moisture in conditions where the windows may fog or
The hybrid/EV powertrain control module 2 requests the AC compressor on to help maintain the battery temperature
The hybrid/EV powertrain control module 2 uses values from the A/C refrigerant pressure sensor, duct temperature sensors, ambient air temperature sensor , passenger compartment temperature sensor, battery cell temperature sensors, battery coolant temperature sensors, and battery coolant pumps to determine the speed at which the compressor will operate. This message is sent from the hybrid/EV powertrain control module 2 to the A/C compressor control module via serial data message.
Ambient Light/Sunload Sensor
The ambient light/sunload sensor includes the sunload sensor and passenger compartment temperature sensor.
This sensor assembly provides information about:
Sun heat intensity
Passenger compartment temperature
The solar sensor is connected to ground and to a 5 V stabilized voltage supply through the HVAC control module. As the sunload increases, the sensor signal voltage also increases and vice versa. The signal varies between 1.4–4.5 V and is provided to the HVAC control module.
The passenger compartment temperature sensor is a negative temperature co-efficient thermistor. A signal and low reference circuit enables the sensor to operate. As the air temperature increases, the sensor resistance decreases. The sensor signal varies between 0–5 V.
Bright or high intensity light causes the vehicles interior temperature to increase. The HVAC system compensates for the increased temperature by diverting additional cool air into the vehicle.
Windshield Temperature and Inside Moisture Sensor
The windshield temperature and inside moisture sensor includes the relative humidity sensor, windshield temperature sensor and humidity sensing element temperature sensor.
This sensor assembly provides information about:
Relative humidity level at windshield (compartment side)
Temperature of the windshield inside (compartment side)
Temperature of the humidity sensor element
The relative humidity sensor measures the relative humidity of the compartment side of the windshield. It also detects the temperature of the windshield surface on the passenger compartment side. Both values are used as control inputs for the HVAC control module application to calculate the fog risk on windshield compartment side and ability to reduce fuel consumption by decreasing A/C compressor power to a minimum without causing any fog. The sensor will also enable partial recirculation mode in order to improve heat-up performance of the passenger compartment under cold ambient temperature conditions without the risk of mist build-up on the windshield. The humidity sensor element temperature sensor supplies the temperature of the humidity sensor element.
When equipped with RPO CE1, the HVAC control module receives this information via serial data from the rain sensor module. When not equipped with CE1, the sensor values are received from signal circuits to the HVAC control module.signal circuits
Here's some info on the auto systems.
The AC compressor function is to provide refrigerant flow in the AC refrigerant loop to help cool down the cabin, help dehumidify the air in a defrost mode and help maintain the battery temperature. Rather than a more-typical pulley, the A/C compressor uses a 3-phase alternating current, high voltage electric motor to operate. It has an on-board inverter that takes high voltage direct current from the vehicle's high voltage battery and inverts it to alternating current for the motor. The AC compressor shall be activated when any of the three following events occur:
The customer pushes the AC button or
The HVAC control, in ECO climate or Comfort Climate Settings, requests the electric AC compressor on to help in cooling the cabin or removing moisture in conditions where the windows may fog or
The hybrid/EV powertrain control module 2 requests the AC compressor on to help maintain the battery temperature
The hybrid/EV powertrain control module 2 uses values from the A/C refrigerant pressure sensor, duct temperature sensors, ambient air temperature sensor , passenger compartment temperature sensor, battery cell temperature sensors, battery coolant temperature sensors, and battery coolant pumps to determine the speed at which the compressor will operate. This message is sent from the hybrid/EV powertrain control module 2 to the A/C compressor control module via serial data message.
Ambient Light/Sunload Sensor
The ambient light/sunload sensor includes the sunload sensor and passenger compartment temperature sensor.
This sensor assembly provides information about:
Sun heat intensity
Passenger compartment temperature
The solar sensor is connected to ground and to a 5 V stabilized voltage supply through the HVAC control module. As the sunload increases, the sensor signal voltage also increases and vice versa. The signal varies between 1.4–4.5 V and is provided to the HVAC control module.
The passenger compartment temperature sensor is a negative temperature co-efficient thermistor. A signal and low reference circuit enables the sensor to operate. As the air temperature increases, the sensor resistance decreases. The sensor signal varies between 0–5 V.
Bright or high intensity light causes the vehicles interior temperature to increase. The HVAC system compensates for the increased temperature by diverting additional cool air into the vehicle.
Windshield Temperature and Inside Moisture Sensor
The windshield temperature and inside moisture sensor includes the relative humidity sensor, windshield temperature sensor and humidity sensing element temperature sensor.
This sensor assembly provides information about:
Relative humidity level at windshield (compartment side)
Temperature of the windshield inside (compartment side)
Temperature of the humidity sensor element
The relative humidity sensor measures the relative humidity of the compartment side of the windshield. It also detects the temperature of the windshield surface on the passenger compartment side. Both values are used as control inputs for the HVAC control module application to calculate the fog risk on windshield compartment side and ability to reduce fuel consumption by decreasing A/C compressor power to a minimum without causing any fog. The sensor will also enable partial recirculation mode in order to improve heat-up performance of the passenger compartment under cold ambient temperature conditions without the risk of mist build-up on the windshield. The humidity sensor element temperature sensor supplies the temperature of the humidity sensor element.
When equipped with RPO CE1, the HVAC control module receives this information via serial data from the rain sensor module. When not equipped with CE1, the sensor values are received from signal circuits to the HVAC control module.signal circuits
I can assure you that this behavior occurs in my vehicle whether in the sun or shade, day or night. Also whether driving or stopped.drdiesel1 said:
My preference for testing in the shade is primarily to eliminate the notion that direct sunlight could have skewed the thermometer readings.
Thank you for the continued info! I'd be interested to know your results if you happen to have the time and opportunity to try my procedure on any other Bolts.
The temperature logger I'm using is the HOBO UX100-011 Temperature/Relative Humidity data logger from Onset, which claims an accuracy of ±0.38ºF. I configure it to store a measurement once every 10 seconds, then I download the data to my Mac via a USB mini cable. Since this was originally bought for work, I happen to be using the Pro version of their HOBOware software, but for this kind of log reading, the free version is likely sufficient to generate a basic graph and/or export the data to something more presentable (such as Numbers or Excel).drdiesel1 said:
The HOBO UX100-001 Temperature-only version might be a less-expensive option, since I haven't seen a need to track humidity.
My dealer has asked me to bring my car back tomorrow so they can perform an "Air Conditioning Diagnostic Test" for General Motors. Not sure what is involved in this test, or even if it will provide them with any relevant information (since if they just set the temperature control to "LO" for example, it will get cold in a hurry!), but I guess more testing is better than no testing?
Has anyone else had a chance to run their climate control at 74º to see if their Bolt heats up?
Has anyone else had a chance to run their climate control at 74º to see if their Bolt heats up?
rybolt said:
I did, as reported above. I'm guessing this affects a significant number of early production Bolts, but maybe they fixed it and you won't see it in recent units. I'm planning to take it in for service, but I'm stalling because I don't enjoy the hassle of dealing with clueless dealer staff and I'm kind of hoping you'll get this all figured out with GM and make it a lot easier for me... :lol:
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