I'm sorry that you had to wait, but I was not near a computer all day. I hope this information is not too late.

The 307 orange wire goes to pin 62 of the interlock ECM on the frame rail. From there the ECM powers the 306 Green wire on pin 64 at the ECM. This wire powers the starter relay. However, before it gets to the relay it changes to an A346 Blue at a harness connector. The A346 blue is the power for the starter relay coil. At the starter relay, when there is power on the blue wire it goes to ground through the coil and closes the magnetic switch in the relay. That allows power to go from the 109 Red to the 304 white that goes to the starter solenoid.

Since the starter works when you power the solenoid, I would work back from there.

I would start at the relay. It is mounted on the left hand wall of the engine compartment. It will have the blue and an orange wire going to the relay coil, a red power supply wire, and the white starter solenoid power wire.

Start by checking power on the red wire, it should have power on it at all times. Then have someone hold the key in the start position and check for power between the blue wire and the orange wire. If this is there, then check for power out on the white.

This should give you a direction to go.

If there is power at the relay on the white, then the wire going to the starter is probably broken.

If there is power at everything else on the relay, but nothing out on the white, then the relay is bad, swap it with the cold start relay that is mounted beside it.

If there is not power between the blue and orange, first make sure the orange shows a good ground. If it does then there is a wiring issue from the ECM to the relay, a wiring issue from the key to the ECM, or the ECM is bad. Check the orange wire at pin 62 at the ECM for power when the key is in the start position and power out on the green at pin 64.

I don't know how long I will be available tomorrow, but if you respond back, I will get back to you as soon as possible.