GM-GMC: Chevy s10 Voltage, chevy s10, battery cables

Question
I have a 1998 S10 2.2L.  Lately the voltage meter keeps surging even after I changed the battery and alternator.  While driving at night, the lights at various times will go dim, but everything works fine if you leave the radio off.

Answer
I do not know if there is/was a recall on the radios, but I do know from GSA vehicle experience that the radios on S-10s of that year caused electrical problems.

If your dealer will not help you, I would remove (or completely disconnect) the radio and see if the problems go away.

The other potential problems of this nature usually involve ground connections.  Look for the cables that connect the engine to frame and the frame to the chassis.  Along with the battery cables, you may wish to remove them, clean them, and reinstall them.