You need to be cautious using dielectric grease on contacts,especially 12 volt connections. Dielectric grease is an insulating grease, so a conducting grease would be a better choice. I brought home, a few little tubes of dielectric grease for my Dad, a number of years ago, so he could use it on his boat trailer to keep the bulbs from corroding from the water when he launched his fishing boat. The next time I visited him, he said the lights weren't working on his trailer. It was the grease, so off to the auto parts store and purchased the correct grease. I did a little research and found this, and I'm sure there are other brands.
http://www.oreillyauto.com/site/c/de...ctrical+grease