with basically the same software to correct a condition caused by corrupted software. Finally, don't neglect software calibrations that are known fixes. Figure 8A shows a compressor drive belt for a GM SUV torn up from the low mounted compressor slugging on start up. Engineers at GM were able to improve the situation with a new calibration (Figure 8B) by gradually applying the clutch during start up. Better living through better software! ■ Photo Courtesy Gates Calibration Chart Courtesy General Motors won't allow you to program a module with the exact same calibration it currently has. While we've all seen nearly miraculous repairs / improvements with TSB documented software updates, occasionally the same software programmed back into the module can solve software lock up or corruption. An automotive electronic module re-flash with the same calibration can be compared to a PC reimage. In both examples, the software is reprogrammed Figures 8A and 8B:This GM SUV was eating belts (Fig. 8A) due to the compressor's low mounting position setting up a slugging condition on start up. The solution was better software. The GM Calibration look up website (Fig. 8B) allows techs to simply type the VIN into the landing page on the free website and go through the process of identifying calibration updates for various modules. Around 60 % of these module updates are documented in a TSB or GM PI (Preliminary Info) while around 40 % are not documented other than through GM's TIS-2 Web (subscription service) or this free website. The recalibration allows the compressor to engage during cranking in order for it to begin running more gradually. MACS Service Reports is published monthly by the Mobile Air Conditioning Society Worldwide. It is distributed to members of MACS Worldwide and is intended for the educational use of members of the automotive air conditioning service and repair industry. Suggestions for articles will be considered for publication, however, MACS Worldwide reserves the right to choose and edit all submissions. Editors: Elvis Hoffpauir, Steve Schaeber Production Designer: Laina Forcey Manager of Service Training: Steve Schaeber Mobile Air Conditioning Society Worldwide P.O. Box 88, Lansdale, PA 19446 Phone: (215) 631-7020 * Fax: (215) 631-7017 Email: membership@macsw.org * Website: www.macsw.org Unless otherwise noted, all photos/art by author. July 2017 8 MACS Service Reportshttp://www.macsw.org