2002 Chevy blazer won't start
I recently replaced my battery and
alternator on a 2002 Chevy Blazer. I
cranked it up and drove it airing for
about 10 minutes and finder see any
indications of battery or charging
problems. It showed a fully charged
battery and never had anthying dim
or fluctuate while driving. Came home
and parked it and it wouldn't start nor
turn over. Went and had both battery
and charger bench tested and they
came back good. What else could it
be? Checked all connections and
made sure all was tight. The
instrument lights come on but no
start.
Your saying the starter motor won't crank the engine? Use a digital multimeter across battery posts, everything off, the generic spec for a full charge is 12.6 volts. If the battery is down use a charger and get it charged up. With meter leads still touching battery posts, have helper turn key to crank, does the reading drop, if so, how far. Generally it shouldn't drop below 9 volts, that spec is subjective, but should be close. With the key in the crank position if no voltage drop or not much, sounds like some kind of open circuit. All connections good, positive and negative? In the diagram, I see four fuses, three of them, hot all the time. The crank fuse goes hot with key in the crank position. Not only check the fuses, use a test light and check voltage on fuse circuits. In the diagram, you can see neutral switch and starter relay. If you suspect the starter, you can take it off, lay it on the ground, hook up jumper cables properly from charged battery to starter motor, at the least it should kick out the drive gear and spin.
If you have a stock Chevy security system you will have to reset it. It has lost the key codes when you disconnected the battery. You should be able to find this information in the owners manual or look it up online.