Try cleaning the contacts and then use dielectric grease sparingly on both ends of the contacts. You might try pipe cleaners and throttle body cleaner. I use this on old steinway pianos with the verdigris. Let the contact thoroughly dry before reconnecting unless you want a small fire. This grease should be on all contacts and connections interior and exterior. In my post about the stubborn seat switches, the switches had dielectric grease installed from the factory.