2000 Oldsmobile Silhouette Will Not Start

Your saying the starter won't crank? How do you know the battery is good? 12.6 volts is the generic spec for a fully charged battery. Check that the battery connections are all clean and tight. Also check the circuits at the crank relay. Terminal 30 is voltage for load side of relay, hot all the time. Terminal 85 is voltage for coil side of relay, goes hot with the key on and is wired through the neutral switch. Terminal 86 is ground, controlled by the pcm, part of security system. Terminal 87 goes hot when the relay is energized, supplies voltage to the S terminal of starter relay, purple wire.

Had intermittent problems with this. After changing battery and alternator, cleaning terminals on starter, checking postive cable, it was the negative ground cable that was loose and corroded, down on the front of the engine. Remove it and do a resistance test on it,wire brush stud, lightly sand the addle ground wires that are with it, sand the surface of the nut that holds this ground wire on. Place all wires back on the ground stud and tighten (assuming this ground wire from your battery is good). Then try to start. FYI: Gravity will carry corrosion down the inside of a positive or negative cable, so there is always the chance you cannot see the corroded part of a ground or starter cable.