Any way to read the Refrigerant Temperature Sensor output?

[Road_Rage]

I have a 2009 Silverado with an A/C issue - it blows ice cold at idle, but at any rpm above idle, it loses the a/c command signal every few seconds and will blow increasingly warmer air until the command returns and the clutch engages again. My pressures appear to be ok, and I'm suspecting it's the Refrigerant Temp Sensor, but it's such a pain to replace that I'd like to verify its output, if possible, before diving in. I can't seem to find any reference to that sensor in the VCM Scanner, however. Is there any way to get a reading from it?

[blindsquirrel]

The service manual says there isn't any such thing as a Refrigerant Temp Sensor - it's not needed, as refrigerant temp is so closely tied to pressure it can know the temp (if that was useful for anything the system needs to do) from the high side pressure sensor alone. There are air temp sensors at various points in the ducting, and an ambient air temp sensor, but that's different and they don't have anything to do with the compressor clutch control, and they all go to the HVAC module anyway, which only a real scan tool would be able to see live data from. Air temp sensors are only used to control the air delivery (blend doors & blower speed).

2009 Silverado non-HP2 autoHVAC compressor controls.png 2009 Silverado non-HP2 autoHVAC temperature sensors.png

[Road_Rage]

Hmmm...I'll have to pull the airbag to verify. YouTube is full of videos on how to replace it, and the parts stores I've checked show one for 08-13 Silverados. I don't know what else it could be that's killing the command signal, unless the compressor relay is going bad. Not sure why it would act up while cruising down the highway and not at idle, though.

[blindsquirrel]

I think getting hold of a tool that can see live HVAC data would be a helluva lot better idea than starting to disassemble things at random based on Youtoob videos.

edit: And also the factory (or equivalent) service manuals.

[blindsquirrel]

HVAC - Automatic - Air Temperature Description and Operation, Document ID 1670922.pdf

Did GM forget to mention that sensor in this fairly excruciatingly detailed description, and also the wiring diagrams/pinouts? Where does it go, what does it connect to? Which module? What is it used for that it doesn't already get from the low side pressure switch & high side pressure sensor? Are my service manuals wrong?