Problem solved. It was the so-called thermal breaker. In checking the operation, I noticed that the relays clicked, but the pump didn't activate. I checked and found no power at the 12v input line to the harness at the relays. I pulled the harness apart and found that the 12v line from the battery splits into three feeds, and was dead. The relays clicked because they are apparently fed from the main Gator electrical harness, not the harness that comes with the plow. The dealer said it could be the control stick, pump, or relays, and was unlikely to be the thermal breaker. The harness with the breaker costs $215, and the pump is over $800. The thermal breaker is in the 12v battery line very close to the battery terminal. I could see two terminals under a rubbery casing. I opened it up, bypassed it, and voila, the plow works perfectly. I searched for a replacement 12v 40 amp breaker, and found that they are used in automotive and marine applications. I found essentially identical breakers ranging in price from $2.29 to $7.99, including some that had a manual reset. I'm going to buy a few. The defective breaker, probably sourced from India, is just a bimetallic strip with welded on electrodes, similar to points in a distributor. The bimetallic strip was off center, and the points were burned. I decided to replace the breaker, rather than just leave it bypassed, as the breaker is there for a purpose, that is, to prevent a short circuit from causing a fire or other calamity.
