Indications show that all grounds are good and:
1. That BOTH outer bulbs low beam filaments are out. (blown or not receiving voltage)
or
2. The low beam circuit has a disconnect/broken wire/short. Starting at dimmer switch low beam output contact and checking voltage all the way to bulb.
or
3. 1 and 2 at the same time...or something causing 2. to blow 1.


Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn