I'm working on my son-in-laws 01 S10 4.3L Automatic. The truck was over heating. I had to replace the intake manifold gaskets. Of course you know what all that involves. After replacing the gaskets and put everything back together, the truck will not turn over, it was running before. All we hear is a click under the dash when the key is turned. I've checked the battery, it has plenty of volts. Any help would be appreciated