Should there be voltage at the ground of the battery? I know it sounds silly but heres the scenario...I had a wire running from the + side of the battery to the interior of the car to provide memory to the stereo. The wire ran into the interior in the same place as the wire/cable from an aftermarket temperature sending unit. The temp sending unit cable got hot and melted the sheath on the battery stereo wire in turn causing a direct short that actually caused a little fire.

So I replaced the battery stereo wire....but now I'm having some weird voltage spikes that are causing any and all of the following: 1. the tach pulses with blinkers. 2. when the headlights are on, they flicker and the oil pressure gauge reacts at the same time of the flicker. 3. Headlights off the blinkers flash at a normal speed...but the headlights on really slow or stop the blinkers. 4.(this is why i ask the initial voltage question)With the headlights on and my voltmeter grounded to the negative post of the battery and the positive to various spots on the frame/body i get 1-2 volts. lights off and the volts go away. Can this be caused by a bad battery?

 

There is a bad ground somewhere. There should be no resistance from Neg. side of battery to the engine block or the cars chassis. Check for loose wires, bad ground connection and such. Maybe check the grounds on the headlights.

 

so...i found a short between my radiator and transcooler. i just cant figure out where its coming from. only when the headlights are on . to fix this i ran amwire from the transcooler to the alternator mount for amground. i justmwant to fix this *** pain and move on. . where is the ground for the headlights?

 

You must have good grounds, all the positive power must get back to the battery. If you have a meter, measure the postive battery post to the power cable at the starter, it should be less than 0.5 volts during cranking. Now, hook the meter from negative side of the battery and the other end to the block, crank the starter, again it should be less than 0.5 volts during cranking. If more clean connections and retest, if still to much the cables are too small of cable size. If #4 guage go to #2 guage, etc. Grounds, if too much voltage is loss and not repaired, the ground WILL find a path. Ground paths = speedo cable or emergency brake cable or drive line ( burn out the grease first then u-joints) or transmission internal parts or cooling system electrolsis or ground wires in wire harness or ??? Add extra grounds using minium 8 gauge wire, keep the wires black, firewall to engine, frame to body panels, battery negative to inter kick panel, voltage regulator to alternator (if seperate), note : they are everywhere!

Dave