Problem resolved. The truck is a messy nightmare in regards to butchered wiring and cleanliness. I started tracing all harness's coming from the starter and relays. I ended up finding two broken ground wires under the control valve. Plus I had to repair a couple other wires that weren't in good shape. I discovered the ground wires accidentally while performing a wiggle test. The relay started clicking and just followed every path until I found them.
Thanks for your help.