Recent content by TJ Baker

  1. T

    No A/C, driving me crazy.

    All of those are not related to the HVAC system decision making process. And the PCM doesn't read ambient temperature at all. The ambient temperature sensor is wired to the HVAC controller, not the PCM. That is almost correct, though the cutout temperature varies among models and such. The...
  2. T

    No A/C, driving me crazy.

    Exactly what PIDS are you reading and monitoring in real time? Ambient temperature?? What app are you using? Using an OBDII adapter you can see high pressure reading. It is available as PID 1144 from the PCM. The equation is where it becomes either the raw voltage reading or the pressure in...
  3. T

    No A/C, driving me crazy.

    And so do I. The low pressure cycle switch is nothing more than an input to the HVAC control module. The HVAC control module sees that as one of several inputs to be used in the decision making process.
  4. T

    Ac Cooling

    Simplest answer is the two vents come from different evaporators. The air from the ceiling outlets comes from the auxiliary system and the air from the panel vents comes from the front system. Further, the front system employs a fixed orifice as a refrigerant meterimg device and the auxillary...
  5. T

    06 Yukon REAR HVAC won't shut off -update, WAS resistor - SOLVED

    For my own curiosity, did your original have a smaller/shorter heat sink than most of the replacements seen online? On mine most all of the replacements I saw online when looking for one showed a heat sink that looked like the one on the front blowers speed module. These physically will not...
  6. T

    06 Yukon REAR HVAC won't shut off -update, WAS resistor - SOLVED

    I wouldn't say they failed or are defective. I think they simply are not the correct design for this vehicle, regardless of what they are labelled or sold as.
  7. T

    Problematic P2135 code

    Possibly useful advisement here.... https://charm.li/GMC/2003/Sierra%20Denali%20AWD%20V8-6.0L%20VIN%20N/Repair%20and%20Diagnosis/A%20L%20L%20%20Diagnostic%20Trouble%20Codes%20%28%20DTC%20%29/Testing%20and%20Inspection/P%20Code%20Charts/P2135/Important%20Information/
  8. T

    06 Yukon REAR HVAC won't shut off -update, WAS resistor - SOLVED

    I believe it,,, see my post #11. They are not properly manufactured for your rear Blower control system. I would say their application listing is incorrect. Good to hear you got it working now.
  9. T

    No A/C, driving me crazy.

    Ambient temperature is outside the vehicle. Inside the vehicle is cabin temperature.
  10. T

    No A/C, driving me crazy.

    Has anyone monitored the AC Request Withheld PID? This parameter lists all the prerequisites for compressor clutch operation.
  11. T

    Suburban died and won't restart (but sometimes it does...)

    Post #13. 2005 Suburban 5.3
  12. T

    California smog i/m 02 sensor code needs complete

    I cannot accurately describe it cause I don't fully grasp it myself!! For the O2 system I/M readiness monitor to update to YES it is more than one test. There are a handfull of diagnostics that must successfully run and pass. Some of these diagnostics run continuously when the proper...
  13. T

    California smog i/m 02 sensor code needs complete

    Have you been able to see what DTC(s) have not run as required for the O2 I/M readiness to update to YES?
  14. T

    Suburban died and won't restart (but sometimes it does...)

    NO!! Replacing a CKP requires a relearn and that requires a $$$ scantool. I would never replace a CKP unless it was conclusively proven bad. Most likely an intermittent electrical issue. When it fails to start, what is seen at the instrument cluster? Security light on ?
  15. T

    06 Yukon REAR HVAC won't shut off -update, WAS resistor - SOLVED

    It bears repeating... Have you verified that your replacements are getting the power, ground, and control input to the locations designated on the new speed control? Here are a pair of diagrams. one has the 12 volt battery power at terminal A and the other has it at terminal C.

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