Should I replace my ignition switch?

What is your question?

recently the check engine light came on in my truck. The codes I scanned were p0740, p0758, p0785, p1860. Before I do it, I wanted to verify. This is where I'm getting confused. I checked the voltage at fuse "ign 0" key on, engine off and I get 12 volts. I pulled the trans pan (needed an oil and filter change anyway) and checked the solenoids. 19.5 ohms on 1-2 and 2-3 solenoids. I then pulled the plug and checked for voltage at the solenoids and have 12 volts. So, I'm at a loss. Do I change the switch hoping this is the cure and these trucks have issues with this. Or do I look further. I didn't get code po753. That's what's throwing me.