1985 Volvo 740 GLE sedan. While car is running, everything
quits. Has happened 4 times in the last 6 months. It loses all
power, has no lights, horn, radio, etc.. It makes no difference
whether the car has been running an hour or 5 minutes. The
battery and alternator have been tested ok. The battery ground
has been checked. The car will start up after sitting, from
overnight to just 10 minutes. Any idea where I should
look next?