Large white wire is ground.
Small white wire or light blue is high mount brake light. (dependent on year of vehicle)
Small brown wire is the marker / clearance / park lights.
Small yellow wire is left turn signal / brake lamp.
Small dark green wire is right turn signal / brake lamp.
Small light green wire is back up/reverse lights.
Large orange wire is battery feed wire.
Large dark blue is the electric brake control wire.
If you have a factory tow package, the factory wires will be bundled in the right rear of the van in the jack storage area.
The other ends of the orange & dark blue wires will be tucked under the carpet in the left front of the vehicle. Like in this pic.
The orange wire (dependant on year) will have a connector on it that will plug into the fuse block.
The dark blue wire will need to be connected to the brake controller output wire.
If you do not have a factory tow package, the wire colors are still the same as above for the lights. You will need to access the wiring at the rear of the vehicle & tap into them for the lights. There is unfortunately, no quick connect plug in that can be used on these vans. The power can be taken off of the 'A' & 'B' power studs in the underhood fuse box to power up the brake controller & the battery feed to the trailer. These studs are fused thru 30 amp maxi fuses.
Brake controller wires are as follows:
The white of the controller gets connected to ground.
The red wire of the controller gets connected to the white wire at the brake pedal switch.
The black wire of the controller gets connected to a fused battery power source. (Stud 'A' or 'B' in the underhood fuse box - '96 & newer)
The blue wire of the controller gets connected to the blue from under the carpet.
](./images/smilies/eusa_wall.gif "Banging my head"){kind=small}