Originally Posted by Damemorder
If it'* not the switch, it must be in the line between the switch and the bulbs since you said you weren't getting power there. The only other way was if you were only getting partial ground at G402, But all the lights on the back of the car ground there.
I'm leaning towards the ground as well. Here'* some info from my diagrams:
Adaptive lamp module:
Pin E - tan/white - runs L & R tail lamps
Pin C - purple - runs L & R tail lamps
Pin D - pink - runs side markers and license plate lamps
G402 - LH rear of luggage compartment, behind wheelhouse.
As this shows, there are different circuits for all of the lamps that are not working. The brown wire is only the park lamps input (pin M) to the ALM. The only common thing is the ground.