Get some 3M rubberized insulating tape that only sticks to itself. Wrap the connection starting from the harness, then onto the connectors and then finish off on the other side on the harness. You'll then have a weather tight seal that you can easily remove later without any mess. You can also put a dab of dielectric grease on the terminal connections to help keep moisture out.
2012 F150 FX4 Ecoboost - FX Lux/Appearance/Navi, Cooper Discoverer 275/60R20s, Hellwig Rear Swaybar, USB2 Mod, Smoked LED Taillights, FX-R HID Projectors