Hi, my mom's old 95 cutlass ciera has been passed around the family many times, but it is really trying my patience lately. A new battery and 3 different alternators later it still spikes to 17+ volts after starting out at 13.6-14 volts. The car always starts cold and runs at normal voltage, but then after it warms up the headlights get real bright, the airbag, check engine and charge lights come on and a volt meter reads 17.5 volts. I am on my third new alternator so that is not the problem. I would appreciate any help. Mike

The voltage regulator and the battery are the only items that control the charging rate. If the battery is fully charged (14.2 volts), then the voltage regulator should shut down the charge rate.
I would replace the battery since you have already tried 3 alternators and each one says keep feeding the battery.

Thanks Doug, I will check out the battery it is probably cooked from over charging. Mike

If your battery check turns up nothing, I would recommend checking the connections for corrosion. Also check the heavy wire between the alternator and starter, and the cable between the battery and starter for breaks. I had an alternator kicking out 23 volts and found the connection at the alternator was bad; no corrosion but instead about 1/4 inch away from the crimped loop connection the tiny wire strands were broke. In my case, a visual inspection revealed burnt wires - the wire color was dull-brown not shiny-copper. A good wire is flexible and can handle a few twists/flexes, a burnt wire is stiff and will break after only a few twists.

Before finding the break, I had very-very-bright headlights/taillights and the same dash lights. The dash lights are caused by an over-voltage error. When the voltage gets too high, the computer will restart itself; the restart feels/sounds likes an ignition misfire.

I would agree with a bad connection in the starting/charging system.

Thiers several fuseable links down by the starter anyone could be fraid/bad and cause over charging. If the battery was bad it wouldnt show 13.6-14 volts.

and Welcome to AF mickeymaster !

Thanks guys, I did find some bad wires that I am in the process of replacing.