Automotive Smart Fuse Aids in Diagnosing Intermittent Shorts (Part 1) (Download)
From navigating the steep and winding roads of mountainous Big Sur, Calif., to wading the treacherous intersections of Cancun during a torrential downpour, my trusty 5-speed, manual-transmission, '94 BMW 325i has been through thick and thin. I love that car but must admit I’ve also had to endure an occasional, pesky, intermittent short circuit that blows a 7.5-A blade fuse.
When the fuse blows, the windows (motors are on separate 15-A fuses) don't work at all, so at a minimum, it's an inconvenience, and at maximum, could mean driving in very poor weather conditions or leaving the car parked with stuck open windows.
That the occurrence is intermittent makes it all the more annoying. It means I can only troubleshoot the problem when it’s present, a sometimes frequent and other times infrequent occurrence—and always of unknown duration. And every time it happens, I have to replace the blown fuse.