Schwintec slide mystery

It has been broke for months now and have been using wire directly to the battery to open and close the 13 foot slide. The first repair was the rails and component on one end of the slide where you find motor #1. It still wouldn't work so Lippert told me it was the #1 motor. I replaced thee motor and it still didn't work. I then I checked the voltage and found out I had a bad 6 volt battery. I replaced all four batteries and the slide then worked once. It then went back flashing the same code that it always had that there was a short between the #1 motor and controller. I did a continuity test on all five wires in the harness to each motor and all is well. I switched the motor harnesses at the controller and still get the same code (#1 motor short in wire) with nothing hooked up. I can hear the click in the controller when the remote button is pushed. The voltage at the controller when the button is pushed is 12.3. I checked the amperage draw when i hooked up the wires to the motor directly.ly to the battery and it started out at 3 amps and increased to 10.1 at the end of the extension. I am using the existing harnesses to get electricity to the motors and is a real time consuming effort. Any help with this mystery greatly appreciated. David