I have a problem with my cobra 12/24v trolling motor. The 12/24 switch (on the foot control) on 12v the motor will turn the prop the correct direction but, on 24v the prop will turn backwards. I have 2 12v trolling batteries in the back of the boat with 4 cables (2 black 2 red) coming from the front of the boat that are conected red to red, black to black. The batteries are charged correctly (not backwards) but I,m not sure what to try. My boat is a 89 Stratos 279 FS w/ a 150 Evinrude.