The head/tail lights and speedometer quit working on my '10 550F Tundra LT. I checked all the bulbs, dried (they weren't wet) and greased the headlights with dielectric grease. I didn't with the taillight. All bulbs looked fine when I looked them over. Dried and greased the speedometers connector too. Still no lights. While running the machine the speedometer lights flicker once in a while though. Would the voltage regulator cause this or something else entirely?