First check battery connections. Loose ground cable coul do it. Then, On the front of the fuse box adjacent to the battery, to the right as you face the engine, there is a silver box, approx 4 inches by 5 inches held on by 4 torx screws. It plugs into the fuse box with many small tabs. Scratch the tabs up with some sandpaper or emery cloth. Tweak them slightly with some pliers so they make a tight fit when plugged back in. Then plug it back in and replace screws. Hard to describe here but it makes sense when you see it.