ACtion Magazine - April 2016 - (Page 14)

MACS Staff For diagnostics, being well grounded in the fundamentals is the key to success. Contributed in part by Bob Chabot, ManicMedia LLC Pete Meier / Motor Age Magazine In addition, he provided a number of A/C and cooling system case studies to demonstrate real world problem solving. Here are some of the key insights he shared. Current has to be in spec for an electrical circuit to operate properly "In the real world, it is unwanted resistance, not changes in voltage, that causes most electrical problems," Pete Meier shared. Every day electrical troubleshooting "Expert mobile diagnosticians tell me that more than 80 percent of what they do everyday ought to be able to be done by any shop technician with good fundamentals," noted Pete Meier, whose Mastering Electrical Troubleshooting seminar at the Mobile Air Conditioning Society's 2016 annual trade show and training event helped shop owners, technicians and educators get a grip on the know-how required to troubleshoot A/C and other issues effectively and efficiently. "That's the good news. It's also the bad news. Getting and keeping a sound understanding of those fundamentals is an increasing problem in modern shops, as vehicles continue to become more electrical in nature and driven by software." Meier's lengthy presentation (now available on the MACS website) covered the resources required to be competent and remain current. 14 ACTION * April 2016 "Anything that alters the ability of current to flow as designed can be considered an 'unwanted' source of resistance," Meier explained. "Examples include an open circuit, shorts to ground, electronic control module parasitic drains and others. Remember that there are also switches and connectors between the two and they have some, but not a great deal of resistance, compared to loads such as motors. "But checking power and grounds on a problematic circuit statically can be a waste of time that will lead you down the rabbit hole," Meier added. "If you cannot perform dynamic voltage drop tests in today's shop, you aren't going to be able to solve an increasing amount of vehicle problems. For example, some automakers are designing-in voltage drops to control operation." To help attendees assimilate the knowledge, Meier described two different ways to perform voltage drop troubleshooting tests, along with a number of case studies with walk-through discussion questions. Diagnosing electrical concerns goes beyond current testing "A complete diagnosis is not limited to just current testing," Meier continued. "Understanding the factors that influence current demand can help you identify and locate a variety of problems, especially in circuits utilizing electric motors or dependent on the strength of a magnetic field - typical in many air conditioning applications." "Many technicians I talk to say parasitic battery drains are more common than they used to be; in particular, drains in circuits controlled by a relay in an Electronic Control Unit (ECU). These components can be difficult to test directly. Examples include A/C compressors mounted in hard to reach areas or fuel pumps immersed inside fuel tanks." Meier showed attendees a test procedure to quickly isolate where the problem

Table of Contents for the Digital Edition of ACtion Magazine - April 2016

ACtion Magazine - April 2016
Training is key offering at 2016 MACS
Networking at MACS
Service Port
Leonard's law
Virtual View
Last Watch
By the Numbers
Cooling Corner
Industry News
Association News
New Products and Services

ACtion Magazine - April 2016