On 2003-2006, if you want:
ONLY door panel lights to come on with door open
ALL lights to come on with the wheel at headlamp switch
Wire up the following:
Cut the gray/black wire on the C3 plug in the relay block. The relay block has the black plastic cover, and it's to the left of the brake pedal. The C3 plug is on the far right.
The circuit is now separated from the "door open" circuit.
To connect it to the wheel at the headlamp switch, you will need to wire a relay to invert the polarity (from positive to negative):
30 - 12V
87 - gray/black
85 - dark blue/white wire, at headlamp switch or BCM
86 - 12V Orange wire, located right next to the gray/black wire. By using this wire, your interior lights will still turn off after 10 mins should you accidentally leave them on.
By doing this mod, opening the rear hatch/cargo door will NOT turn on any lights.