Chevrolet Trailblazer Starter Relay Replace/Remove

Hello I Have A Question My Truck Wont Start But All The Lights Are On And Everything Works And I Changed The Starter Relay But It Still Wont...

My Trailblazer Will Not Crank Or Start. I Have Replaced Starter, Starter Relay, And Ignition Switch. Does Nothing. I Was Thinking It Was An...