12v symptoms I don't understand
Today while switching out 12v batteries my wrench momentarily shorted positive to trailer body (it sparked a little), I already had negative connected. Since then it appears that I only have 12v power...
Forum Discussion
Harvard wrote:
The very instant in time that the wrench touches the frame kicks off a series of high frequency events. These high frequency events pack a tremondous amount of energy. At high frequency, all conductors become inductors (high impedance) and all capacitance becomes conductors (low impedance). The wire conductor from CHASSIS to BATT MINUS becomes the most significant inductor and allows the BATTERY to spike up to thousands of volts taking the +12 VDC wiring along for the ride. What this all means is during the arcing process there are AC voltages generated at amplitudes thousands of times the applied 12V battery. This high frequency activity may be too short in duration to blow fuses but pack a high enough voltage to blow Field Effect Transistors (FETs and MOSFETs). JMO.
Yes, which is why I'd start at a non-working device and see if it's getting 12v power. If it is, and it doesn't work, the device is broken and the focus needs to be on the fixing the broken device. It could be anything from a fuse to an active component as described above. OTOH, if the non-working devices are not getting power, the problem is in the 12v system, not the device and it's likely to be a bad ground, a blown fuse, a burnt out wire, etc.
