2007 Hummer H2 HVAC/TEMP issues
#11
05-09-2019, 02:02 PM
i also believe there is a GM TSB on the snowflake issue with those climate controls where they switched the function of what the snowflake means. in some years the symbol being off meant it was working in other years it meant it is off. i do not recall if 2004 was the teetering point.
#12
05-09-2019, 02:44 PM
All of these issues are caused by a temp sensor that has failed of the wiring has issues. You need a scanner and investigate what the ECM is seeing for a ambient temp. in certain cases the BCM will see a short to ground and then default to a temp that is within a range that will allow the AC to function correctly. Not going to recirc is also a function of the ambient temp being out of range in certain conditions.
Neal
Neal
#13
05-30-2019, 11:10 AM
I have searched a lot on these topics but cant quite locate what I am looking for or maybe I am just over looking the correct thread.
My first issue is my DIC displays "ice possible" when the temp on the mirror shows to be over 60 degrees. Not a huge issue but there is obviously a problem. My suburban does this but when it is actually very cold out and the compass will read "ICE" but the hummer will not display that it actually shows pretty close to the temp that is outside.I have replaced both temp sensors located under the hood. This issue will also prevent the AC from coming on because something is telling the truck it is cold outside. Like the temp on the compass will read 64 but the " ice possible" message will display on the dash . Even sometimes it will be well over 90 degrees or even over 100 and the AC wont come on, it blows the air but when you hit the snowflake button the little amber light on it just flashes. It literally just works when it wants to and in this Texas heat I can't have that in an all black SUV. Which brings me to my second issue. I assumed the HVAC system was the same on my suburban as the H2 so when I realized this AC gets no where as cold as the suburban I assumed there was an issue. It will not cool the truck off by any means even after driving for an hour. Also there is no air coming out of the center console vents for the rear. I have tried resting the HVAC system, I pulled the fused wait awhile then turned the key on but did not start it, I could head all the actuators moving around and it defaulted the temp at 74 degrees so I assumed the system actually rested.
I have read forums for awhile now and noticed people are always posting things in the wrong section, I hope I have not done this and I apologize if I have. Also thank you to anyone who can provide any help on these issues.
My first issue is my DIC displays "ice possible" when the temp on the mirror shows to be over 60 degrees. Not a huge issue but there is obviously a problem. My suburban does this but when it is actually very cold out and the compass will read "ICE" but the hummer will not display that it actually shows pretty close to the temp that is outside.I have replaced both temp sensors located under the hood. This issue will also prevent the AC from coming on because something is telling the truck it is cold outside. Like the temp on the compass will read 64 but the " ice possible" message will display on the dash . Even sometimes it will be well over 90 degrees or even over 100 and the AC wont come on, it blows the air but when you hit the snowflake button the little amber light on it just flashes. It literally just works when it wants to and in this Texas heat I can't have that in an all black SUV. Which brings me to my second issue. I assumed the HVAC system was the same on my suburban as the H2 so when I realized this AC gets no where as cold as the suburban I assumed there was an issue. It will not cool the truck off by any means even after driving for an hour. Also there is no air coming out of the center console vents for the rear. I have tried resting the HVAC system, I pulled the fused wait awhile then turned the key on but did not start it, I could head all the actuators moving around and it defaulted the temp at 74 degrees so I assumed the system actually rested.
I have read forums for awhile now and noticed people are always posting things in the wrong section, I hope I have not done this and I apologize if I have. Also thank you to anyone who can provide any help on these issues.
#14
11-14-2019, 06:31 AM
There are also two temp sensors in the ductwork in the dash and one over your head behind the microphone in the other tiny grille on the ceiling.... Does not seem like those would be the one the DIC message is based on but maybe one is. The two by the pass headlight are the HVAC and mirror ambient temp sensors. One in the headliner is the inside air temp sensor and the two in the ducts are for left and right temp sensing. So my only other guess would be the one in the headliner.
It just seems highly unlikely to me though. My guess - wiring fault. The temperature sensors are resistance based. The temperature changes the resistance. If there is a connector either right at the sensor, inline harness connector, or at the BCM that the pin in the connector is come loose this could very much be the cause. You could rule out the sensor itself by just swapping the two of them. If one is bad than you would get a bad temp reading on the mirror instead of ice possible on the DIC. The ice possible message is a class 2 bus message sent from the BCM to the DIC in the instrument cluster. That same sensor also is used for the AC when in its "automatic mode". So that might also be a clue in that the temps in the automatic mode will also get wonky as it uses data from that same sensor, the sun load sensor on the dash, as well as the inside temp sensor to determine the correct settings in the auto mode.
It just seems highly unlikely to me though. My guess - wiring fault. The temperature sensors are resistance based. The temperature changes the resistance. If there is a connector either right at the sensor, inline harness connector, or at the BCM that the pin in the connector is come loose this could very much be the cause. You could rule out the sensor itself by just swapping the two of them. If one is bad than you would get a bad temp reading on the mirror instead of ice possible on the DIC. The ice possible message is a class 2 bus message sent from the BCM to the DIC in the instrument cluster. That same sensor also is used for the AC when in its "automatic mode". So that might also be a clue in that the temps in the automatic mode will also get wonky as it uses data from that same sensor, the sun load sensor on the dash, as well as the inside temp sensor to determine the correct settings in the auto mode.
Thanks
#17
11-14-2019, 01:08 PM
The GM docs says the upper right one you can reach through the glovebox. Open the glovebox, empty it, the you can pull the inside edges in that catch it from falling open and let its lid hang loose.
The upper left one - you access like you would to remove the stereo which is a bit involved. To get the center stack trim panel off you have to first remove the bucket in the floor console, 4 10mm bolts under that, remove shifter handle, cupholder/shifter trim, one more 10mm bolt under there, then 2 7mm screws go through the floor console forward into the center stack trim panel, then you can slide the entire floor console back, then remove the center trim panel.
Lower left it says to just reach under and unplug it.
Lower right says to remove the lower insulator panel which is attached form underneath with 4 screws (probably 7mm) to reach it.
The upper left one - you access like you would to remove the stereo which is a bit involved. To get the center stack trim panel off you have to first remove the bucket in the floor console, 4 10mm bolts under that, remove shifter handle, cupholder/shifter trim, one more 10mm bolt under there, then 2 7mm screws go through the floor console forward into the center stack trim panel, then you can slide the entire floor console back, then remove the center trim panel.
Lower left it says to just reach under and unplug it.
Lower right says to remove the lower insulator panel which is attached form underneath with 4 screws (probably 7mm) to reach it.
#19
11-15-2019, 07:48 AM
I don't mean to hijack this thread but after using the tech 2 I found that I have 2 codes in the DTC PO164 and PO229. Looking for the Passenger compartment temp sensor I learned PO removed it at some point in its lifetime as there is no spot on headliner where it should be, inside temp on tech 2 says 131 deg, seems I now need to find those wires put a new plug on them and relocate it somewhere in the cabin area 
The other code seems to be pointing to the actuator that needs the complete dash removed . Any ideas from the experts
The other code seems to be pointing to the actuator that needs the complete dash removed . Any ideas from the experts
#20
11-19-2019, 05:27 AM
Just checking your DTC codes, is P0164 = B0164 and P0229 = B0229? my GM Service Database lists them as "Bxxxx" rather than "Pxxxx" (confusing)
?0164 = Passenger Compartment Temperature Sensor Circuit Range/Performance
?0229 = Recirculate Position Feedback Circuit Range/Performance
Also confusing for ?0164 is the Service Info refers to the "Passenger Compartment" and also the "Inside Air Temperature Sensor Assy" so it's not exactly clear which sensor is being referenced here.
The Recirculation Actuator (Top Front of HVAC Assembly) is related to the ?0229 DTC
According to the wiring diagram, there are 6 temperature sensors (thermistors)
All thermistors are NTC (Negative Temp Co-Efficient) so resistance goes down with increased temperature, range -40F to +215F, 5V to 0V
I'm not super sure of the location of the Inside Air Temperature Assembly, so if this is the issue has something been changed? Presumeably the connector and wiring will still be there and in the position where it should be?
Could the two codes are linked by physical location such as the I/P Junction Block (Lower Right Side of Dash) ? (See attached pdf)
Keep us posted.
?0164 = Passenger Compartment Temperature Sensor Circuit Range/Performance
?0229 = Recirculate Position Feedback Circuit Range/Performance
Also confusing for ?0164 is the Service Info refers to the "Passenger Compartment" and also the "Inside Air Temperature Sensor Assy" so it's not exactly clear which sensor is being referenced here.
The Recirculation Actuator (Top Front of HVAC Assembly) is related to the ?0229 DTC
According to the wiring diagram, there are 6 temperature sensors (thermistors)
- Upper Right Air Temperature Sensor (At Right Side of Dash Panel)
- Upper Left Air Temperature Sensor (At Left Side of Dash Panel)
- Lower Right Air Temperature Sensor (Middle Right Side of Dash, In Front of Rectangular Dishcharge Duct)
- Lower Left Air Temperature Sensor (Middle Left Side of Dash, Under Left Round Discharge Duct)
- Inside Air Termperature Sensor Assembly (Motorised Fan)
- Ambient Air Temperature Sensor (Right of Radiator Support)
All thermistors are NTC (Negative Temp Co-Efficient) so resistance goes down with increased temperature, range -40F to +215F, 5V to 0V
I'm not super sure of the location of the Inside Air Temperature Assembly, so if this is the issue has something been changed? Presumeably the connector and wiring will still be there and in the position where it should be?
Could the two codes are linked by physical location such as the I/P Junction Block (Lower Right Side of Dash) ? (See attached pdf)
Keep us posted.