Re: 91 Explorer Electrical Problem
In article <sZMne.firstname.lastname@example.org>,
"Paul" <email@example.com> wrote:
> My 91 with 126 K miles has a problem with the electrical system. Volt meter
> on the dash wanders on the high side. I have put a voltmeter across the
> battery with the engine running and read 14.5 to 15.5 with a steady
> frequency. Engine off, battery reads 12.97 volts. Checked the alt at
> Autozone on and off the car and its okay,
> replaced the voltage regulator just to be sure and it still wanders. Any
> ideas? Thanks, Paul.
15.5 volts is too high, the fact that it cycles between there and
14.5 possibly suggests that there is a diode problem.
Connect your VOM between the alternator output stud and battery
negative, set the meter to AC volts, start the engine, if the AC
voltage (ripple test) is near or above 100mv, there is a diode
Parts store diagnostics are iffy at best.