Truck quit running at stop sign. Tried to start but only made a loud clicking noise from the starter.

Tried jumping off with no luck, starter only make a loud clicking noise.
Changed battery and no change, replaced starter and still no change.

The truck will not turn over at all, only loud clicking from starter when I try to start it. Decided to see if motor locked up, removed 1 spark plug and while turning the harmonic balancer big nut helper could look into the cyclinder and see the piston moving up and down.

Check ground cable to motor, battery cable ends and still only makes loud clicking noise from starter and will not spin the motor.

Thanks for any help

 

Check power feed to starter. Battery to PDC, PDC to starter. I think there is a fusible link at the PDC.

 

As you can tell by my post not a mechaic for sure. What is the PDC? Thanks

 

Power Distribution Center. The fuse box under the hood, on the drivers side fender.