Hello all: My Climate control system (04 Suburban Z71 4X4) is giving me fits. on occasion it fails to engage the compressor. I've tried a new Dorman Digital dashboard control module (which drained my battery because I don't drive the truck enough) and now have a remanufactured OEM control module which worked for a couple of days perfectly. I turned on the system the following day and got nothing but hot air. I shut the engine down, waited a few minutes and it came on blowing cold air. I'm at the point of being suspicious of the ECM. Does the Climate control module communicate with the ECM to engage the compressor or does the Control module communicate directly with the compressor?

If through the ECM then either the control module is not communicating with the ECM or if it is, the ECM is not executing a command to activate the compressor. This issue caused me to replace the control module but now 2 replacement modules later, Its still exhibiting the same malfunction. If it is the ECM would there be a code stored which can be read by an OBD? Can it be corrected or does the ECM need to be replaced? Who is the best source for remanufactured ECMs? Any suggestions would be most appreciated.

 

Did you check to see if the system is fully charged with freon?

 

Thank you for the reply. Yes on several occasions. Everything else in the system has checked out ok.