I bought my 1994 Chevrolet Corsica brand new and it has no modifications.
The car is well taken care of, has a 6 cylinder engine with 155,000 miles,
is in excellent condition and has never given me any problems until now.

For the past few months the vehicle's electrical system intermittently
surges from 12 volts to 19 volts (according to my voltmeter) at random
times. When it surges up, a red light on the instrument panel that is shaped
like a battery comes on. When it drops back down to 12 volts the light goes
out.

When it surges up, my headlights get very bright and my heater blower speeds
up. I have replaced 4 headlight bulbs in as many months but nothing else has
blown out.

Sometimes the power surges up and down every few seconds, while at other
times I can drive for hours without it surging at all. I have never smelled
anything burning, nor have any of the fuses been warm to the touch when I
touched them.

It does surge more often at high RPM than low. However, it sometimes doesn't
seem to be affected by RPM. Sometimes it is fine until I accelerate at which
time it surges, while at other times it doesn't surge at all when I
accelerate.

I cannot find a pattern to this in regards to hitting bumps in the road,
temperature and humidity, etc. The only item of auxiliary equipment in the
car is a police scanner and I have verified that it is properly connected to
the vehicle's electrical system. None of these seem to be the cause.

Due to the fact that I am worried that the car will become damaged, I have
installed a brand new battery, alternator (that contains an internal voltage
regulator), and battery cables. I have made a visual inspection of the many
wires and cables under the hood and they all appear to be sound and in good
condition.

Will someone in this newsgroup please give me some advice on what to look
for? Thank you for the assistance.