drdiesel1
Posts: 128
Joined: Mon Jan 09, 2017 5:41 am

Re: Is HVAC burning you up too? Chevy says "nothing wrong"

Thu May 04, 2017 12:29 am

rybolt wrote:
drdiesel1 wrote:
phil0909 wrote:ontheseven - Guess it's not all of us, then. Thanks.
Dr. D - Thanks for the info. My dealer was not helpful either.

Talk to the dealer and tell them about that TSB. It's not a software update. I'll post the gist of it for you.

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?

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...


No, don't worry about it. You have the problem, so DTC's aren't required. Tell them to actually READ the TSB
and stop interpreting it.....................:idea:

rybolt
Posts: 30
Joined: Fri Mar 03, 2017 1:12 am

Re: Is HVAC burning you up too? Chevy says "nothing wrong"

Sat May 06, 2017 2:23 am

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.
RYBOLT 05-04-17 Dealer Diag.png
Graph of my Bolt's cabin temperature (blue) and climate setting (green) while at the dealer
RYBOLT 05-04-17 Dealer Diag.png (166.5 KiB) Viewed 4386 times

Service statement.JPG
Technician's notes as they appear on my service documentation 04-MAY'17
Service statement.JPG (138.28 KiB) Viewed 4386 times

Test at 74F full auto.JPG
How to set your climate control for testing at 74º F
Test at 74F full auto.JPG (178.41 KiB) Viewed 4386 times

jostafew
Posts: 12
Joined: Thu Dec 01, 2016 12:20 am

Re: Is HVAC burning you up too? Chevy says "nothing wrong"

Sat May 06, 2017 4:39 am

My two new digital thermometers (with remote probes) just arrived and the logging thermometer should be here in a week or two. I'll be adding some data to your findings here soon.

drdiesel1
Posts: 128
Joined: Mon Jan 09, 2017 5:41 am

Re: Is HVAC burning you up too? Chevy says "nothing wrong"

Sat May 06, 2017 5:14 am

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

rybolt
Posts: 30
Joined: Fri Mar 03, 2017 1:12 am

Re: Is HVAC burning you up too? Chevy says "nothing wrong"

Sat May 06, 2017 5:24 am

drdiesel1 wrote:You might be fooling the auto settings with the car in the shade :idea:

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.

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.

drdiesel1
Posts: 128
Joined: Mon Jan 09, 2017 5:41 am

Re: Is HVAC burning you up too? Chevy says "nothing wrong"

Sat May 06, 2017 5:30 am

rybolt wrote:
drdiesel1 wrote:You might be fooling the auto settings with the car in the shade :idea:

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.

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.


I will get my thermometers from work and follow your info and see what I can get. Do you have a link for the
data logging device ? Thanks!

rybolt
Posts: 30
Joined: Fri Mar 03, 2017 1:12 am

Re: Is HVAC burning you up too? Chevy says "nothing wrong"

Mon May 08, 2017 9:39 pm

drdiesel1 wrote:I will get my thermometers from work and follow your info and see what I can get. Do you have a link for the data logging device ? Thanks!

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).

The HOBO UX100-001 Temperature-only version might be a less-expensive option, since I haven't seen a need to track humidity.
HOBO-UX100-Temp-RH-25-Data-Logger-UX100-011.jpg
HOBO-UX100-Temp-RH-25-Data-Logger-UX100-011.jpg (2.52 KiB) Viewed 4220 times
HOBO-UX100-Temperature-Data-Logger-UX100-001.jpg
HOBO-UX100-Temperature-Data-Logger-UX100-001.jpg (3 KiB) Viewed 4220 times

rybolt
Posts: 30
Joined: Fri Mar 03, 2017 1:12 am

Re: Is HVAC burning you up too? Chevy says "nothing wrong"

Wed May 10, 2017 4:22 pm

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?

michael
Posts: 651
Joined: Thu Jan 29, 2015 10:13 pm

Re: Is HVAC burning you up too? Chevy says "nothing wrong"

Wed May 10, 2017 6:05 pm

I took a test drive in two cars an both seemed to work normally
2013 Ford Focus Electric 51000 miles in 34 months, returned
2014 Volt, returned
2014 Volt, returned,

2017 Volt
2017 Volt
1967 Corvette 427
1962 Corvette 327

phil0909
Posts: 269
Joined: Thu Jan 05, 2017 7:25 pm

Re: Is HVAC burning you up too? Chevy says "nothing wrong"

Wed May 10, 2017 6:14 pm

rybolt wrote: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?


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:

Return to “Technical Discussions”