OK, I've been around cars for almost fifty years and just heard a new one that I put in the old wives tales (BS) column. I was working the Fort Worth Auto Show the past few days where our Mustang Club had a display of 7 cars. Since it was an indoor show the batteries had to be disconnected. In all my years I had always disconnected the ground (-) terminal first because if while doing this you touch your wrench to any metal nothing will happen. Well one of our younger members insisted that you have to disconnect the positive (+) terminal first or it will do something terrible to the ECU. By doing it in this order one takes a chance in grounding out the wrench causing massive schpitzen-schparken. I say killing power is killing power regardless of which terminal is disconnected.
If I am wrong, convince me how.
2002 Black GT (Spectre)
2011 Red Candy Metallic V6 (Manfred)
2016 Magnetic Metallic GT (MkIV)