My 2000 Blazer with the vortec 4.3 not start. I did charge the batteries and it had just over 12 volts when I was trying to start it and all it wants to do is just click. So I'm pretty sure the battery is good could it be the leads going to the battery? I am an air force train aerospace run equipment mechanic but gasoline engines are not my thing so any advice would help.

 

Welcome to the forum.

Make sure your battery cables are tight and clean and there are no damaged or frayed cables.

A fully charged battery reads 12.6V, what is your reading after charging with everything off? BTW, 12.0V is under a 50% charge.

The battery has to maintain a certain voltage under the load of the starter, what is the voltage at the battery when you are attempting to start the truck?

When you attempt to start the truck what is the voltage at the crank fuse, 10A in the UHFB?

Report back and we'll get you fixed up.


George