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.