This is where I bought parts for my MK. There are schematics an parts diagrams here too -
http://www.trollingmotorparts.com/De...ookieSupport=1
As Travis said, Marine Electric will get you squared away or to discuss the problem with another expert contact John Jones, he's a great guy and might be able to pin point the problem -
http://www.jonestrollingmotor.com/