We all have things that we must do, but would rather put off indefinitely. At the top of my list is taking my car into the dealer for service, even for a simple oil change. Just the thought of it makes my heart race, my blood pressure rise, and my voice utter squeaky sounds. Why? Because I doubt the mechanic had ever earned an engineering degree. Without the degree, it is not likely he would know how to diagnose a problem that his hand-held vehicle computer scanner could not analyze.
I know mechanics are “certified” after having had training at a licensed school. When I was the engineering manager of an automotive diagnostic test equipment manufacturer, I attended several General Motors mechanics’ classes and received certificates that qualified me to repair ignition systems, onboard computers, electrical systems, emission systems, and more. But I also have an electrical engineering degree. I attended the classes so I could rub shoulders with “real” mechanics and find out what kind of test equipment they needed to do their jobs. Multimeters and oscilloscopes were the best test instruments we could offer in the early 70s, but when onboard computers became more widespread, hand-held scanners were necessary.
But diagnostic scanners cannot solve all problems. Mechanics still cross-thread oil pan plugs, break gaskets and seals, forget to replace anti-vibration snubbers and brackets, and worst of all, cannot fix electrical problems that are not programmed into the scanner. For example, the last time I took my car in for routine maintenance, I told the mechanic that my power seat did not operate after my previous visit. I had looked in the fuse box and discovered a blown 30A fuse. The load for that circuit comprised the forward-reverse motor, the up-down motor, and the lumbar pad.
Obviously, the scanner would not diagnose such a problem, so I expected the technician to check the seat for pinched and shorted wires, a jammed track that would stall one of the motors, or a shorted motor winding. After two hours, I was informed that I would have to return the following week to have the defective lumbar switch replaced because it had to be specially ordered. I wondered how a defective switch could blow the fuse, so I asked the technician how he diagnosed the problem. He replaced the 30A fuse with a 40A fuse, and when he pushed the lumbar switch, it smoked, and the fuse blew! He deduced that it was, therefore, a defective switch because it smoked! I asked him what instruments he used to diagnose the problem and he said, “My nose and my eyes!”
After I left the dealership, I checked the circuit myself and measured the isolated motor current to be 8.5A and the lumbar circuit to be 1.5A. I examined all the wires, cables, and seat tracks and found nothing wrong. So, I replaced the incorrect, blown 40A fuse with the proper 30A fuse, and everything worked just fine. Unfortunately, I might not have solved the problem either, since it could be an intermittent “short circuit”, but now I know that the circuit should only draw 10A maximum, and it is protected by a 30A fuse that can handle the inrush current plus a little more – and certainly blow if the “short” shows up again.
This technician was certified, but he lacked very basic knowledge about simple circuits. Should we expect him to understand basic electronics? I would expect it if he was an electronics technician, but these techs work on everything. If anything, they need a Mechatronics degree or similar training. But, I just ask that they get a tougher instructor, learn to use a multimeter, and be required to update their knowledge annually. Finally, at least one person on the team should be an electronics technician. What do you think? Tell me on the Engineering Exchange.