We have an SD70 at work here and there are 2 problems with it. One, the high speed solenoid on the right side of the engine will not kick in. If we unplug the connection, we have volts on both high and low speeds but it will not kick in. Problem with the solenoid or could it be with the command protector? Also, the fuel shut off solenoid will not kick on when the key is turned. We have to use a tie wire to keep the engine running. Is there any way to test the solenoid on the bench?
probe the wires closest to solenoid and give power and ground accordingly from a battery source if solenoid doesnt actuate you know its bad