Check the voltage at the bow where it connects into the 597C. I had a similar issue in the past where the wire feeding it was shorting out; not a complete short, but was just enough to drop the voltage to under 12V. Some units shut down if the voltage is below a certain value.
You can also troubleshoot by running a new wire directly from the battery to the 597C to see if it powers on without the big motor. If it does, replace the wiring with new. Good luck