Assuming a chrome bumper the main rear light clusters and the front
parking/indicator light units are earthed separately through their physical
mountings, so a single earth fault isn't going to stop all of them working
at once. Whilst the rear side markers do earth at that number plate bolt so
do the reversing and number plate lights, so if the former are working it
isn't that earth. The front side markers earth with the headlights, to a
single point near the starter relay, so if the headlights are working it
isn't that earth either.
----- Original Message -----
> I'd check grounds first. The tail lights and fuel pump ground at one point
> inside boot right behind the number plate.